Download presentation
Presentation is loading. Please wait.
Published bySheila Goodkind Modified over 10 years ago
1
Centers for Disease Control and Prevention David J. Sencer CDC Museum Tom Harkin Global Communications Center June 4-8, 2012 Teach Epidemiology Professional Development Workshop Day 3
2
2
3
3 Teach Epidemiology
4
4 Time Check 8:15 AM
5
5
6
6 Teach Epidemiology
7
Teach Epidemiology Workshop—Day 2 Diane Marie M. St. George, PhD University of MD School of Medicine
8
Back to EU 2 and 3 Why study patterns of disease? Why is a description of the person, place, and time elements of a disease distribution important?
9
Epidemiologic Studies Descriptive epidemiology Describes patterns of disease Suggests hypotheses about relationships between “exposures” and “health-related conditions” Analytic epidemiology Tests hypotheses Evaluates relationships Always in a search for causality Knowing causation helps us to prevent and treat disease and promote health
10
Enduring Understandings 4. A hypothesis can be tested by comparing the frequency of disease in selected groups of people with and without an exposure to determine if the exposure and the disease are associated. 5. When an exposure is hypothesized to have a beneficial effect, studies can be designed in which a group of people is intentionally exposed to the hypothesized cause and compared to a group that is not exposed. 6. When an exposure is hypothesized to have a detrimental effect, it is not ethical to intentionally expose a group of people. In these circumstances, studies can be designed that observe groups of free- living people with and without the exposure.
11
Testing hypotheses about BrCA Hypothesis: High dietary fat intake increases risk of BrCA. Evaluate the hypothesis using a: Case-control study
12
Case-control study of dietary fat and BrCA Exposure is diet Measured as dietary fat intake (FFQ) Outcome is BrCA Measured as yes or no Want to ensure that you have enough cases to do your study, so recruit participants with BrCA Find those without BrCA Ask them about diet What might you expect to see?
13
Diet and BrCA BrCA+BrCA- High fat Low fat 100 200
14
Diet and BrCA BrCA+BrCA- High fat601070 Low fat4090130 100 200 What is the prevalence of BrCA?
15
Case-control Study Odds = probability an event will occur/probability that an event will not occur Odds of exposure in cases = (among cases) probability of being exposed/probability one was not exposed What is odds of exposure in controls? = (among controls) probability of being exposed/ probability one was not exposed What is Odds Ratio?
16
Diet and BrCA BrCA+BrCA- High fat601070 Low fat4090130 100 200 What is the odds of exposure among the cases? What is the odds of exposure among the controls? What is the OR?
17
Diet and BrCA BrCA+BrCA- High fat601070 Low fat4090130 100 200 What is the odds of exposure among the cases? (60/100)/(40/100) = 60/40 = 1.5 What is the odds of exposure among the controls? (10/90) =.11 What is the OR? ~ 13.5
18
Case-control Study Key elements Compare individuals selected on the basis of disease status Classic epidemiologic study design Quantify association Odds Ratio Advantages Can be less expensive and time-consuming than follow-up studies Efficient for rare diseases Disadvantages May be resource-intensive because of need to screen so many Difficult to assess temporality
19
Testing hypotheses about BrCA Hypothesis: High dietary fat intake increases risk of BrCA. Evaluate the hypothesis using a: Cohort study
20
Cohort study of diet and BrCA Exposure is diet Measured with food diary Outcome is BrCA Measured as yes or no Want to ensure that you have enough exposed persons to do your study, so select for those with high fat intake Find those with low fat intake Follow them up over time to ascertain BrCA status What might you expect to see?
21
Diet and BrCA BrCA+BrCA- High fat100 Low fat100 200
22
Diet and BrCA BrCA+BrCA- High fat7030100 Low fat3565100 10595200 What is the incidence of BrCA among those with high fat intake? What is the incidence of BrCA among those with low fat intake? What is the risk ratio?
23
Diet and BrCA BrCA+BrCA- High fat7030100 Low fat3565100 10595200 What is the incidence of BrCA among those with high fat intake? = 70% What is the incidence of BrCA among those with low fat intake? = 35% What is the risk ratio? = 2.0
24
Cohort Study Key element Select based on exposure status and follow-up over time Quantify association Relative risk (risk ratio) Advantages Minimizes confusion about temporality Ideal for rare exposures Disadvantages May have to screen many to get exposed group Large, time-consuming, expensive especially if disease is relatively rare and/or slow to develop Inefficient for rare diseases
25
Testing hypotheses about BrCA Hypothesis: High dietary fat intake increases risk of BrCA. Evaluate the hypothesis using a: Randomized controlled trial
26
RCT study of diet and BrCA Exposure is diet Measured as dietary fat exposure Outcome is BrCA Measured as yes or no Want to ensure maximal control over study parameters, so you decide who gets exposed and who does not Follow up over time to ascertain BrCA status What might you expect to see?
27
Diet and BrCA BrCA+BrCA- High fat Low fat 200
28
Diet and BrCA BrCA+BrCA- High fat7030100 Low fat3565100 10595200 What is the incidence of BrCA among the high fat group? What is the incidence of BrCA among the low fat group? What is the risk ratio?
29
Diet and BrCA BrCA+BrCA- High fat7030100 Low fat3565100 10595200 What is the incidence of BrCA among the high fat group? = 70% What is the incidence of BrCA among the low fat group? = 35% What is the risk ratio? = 2.0
30
Randomized Controlled Trial Key elements Assign treatments to individuals and follow up to ascertain disease status. The researcher controls primary exposure under study. Exposures can be treatments (drug, surgery) or preventive measures (water fluoridation, exercise regimens). Ethical considerations may preclude use of this design. Quantify association Relative risk (risk ratio) Advantages Random assignment serves to “equate” groups Closest to “true experiment” Disadvantages Expensive and time-consuming Subjects are often highly selected group because the requirements of participants can often be extensive
31
31 Time Check 9:45 AM
32
32
33
33 Teach Epidemiology
34
34
35
35 National Research Council, Learning and Understanding Teach Epidemiology Enduring Epidemiological Understandings Knowledge that “… is connected and organized, and … ‘conditionalized’ to specify the context in which it is applicable.”
36
36 Association Found Between Coffee and Pancreatic Cancer Associated Teach Epidemiology
37
37 What do we mean when we say that there is an association between two things? Associated TiedRelated Linked Things that are associated are linked in some way that makes them turn up together. Associated Teach Epidemiology
38
38 Things that are associated are linked in some way that makes them turn up together. Associated Teach Epidemiology
39
39 Suicide Higher in Areas with Guns Smoking Linked to Youth Eating Disorders Snacks Key to Kids’ TV- Linked Obesity: China Study Family Meals Are Good for Mental Health Lack of High School Diploma Tied to US Death Rate Study Links Spanking to Aggression Breakfast Each Day May Keep Colds Away Study Concludes: Movies Influence Youth Smoking Study Links Iron Deficiency to Math Scores Kids Who Watch R-Rated Movies More Likely to Drink, Smoke Pollution Linked with Birth Defects in US Study Depressed Teens More Likely to Smoke Associated Teach Epidemiology
40
40 Epidemiologic studies that are concerned with characterizing the amount and distribution of health and disease within a population. Descriptive Epidemiology Teach Epidemiology
41
41 Epidemiologic studies that are concerned with determinants of disease and the reasons for relatively high or low frequencies of disease in specific population subgroups. Analytical Epidemiology Teach Epidemiology
42
42 Hypothesis Formulating Descriptive Epidemiology Testing Analytical Epidemiology An unproven idea, based on observation or reasoning, that can be supported or refuted through investigation An educated guess Hypothesis Teach Epidemiology
43
43
44
44 Making Group Comparisons and Identifying Associations Teach Epidemiology
45
45 Hypothesis: Buprenorphine will stop heroin addicts from using heroin. Making Group Comparisons and Identifying Associations Teach Epidemiology
46
46 Population Trial 1 Making Group Comparisons and Identifying Associations
47
47 Population 500 Heroin Addicts Sample 100 Heroin Addicts 10 Weeks Trial 1 Making Group Comparisons and Identifying Associations
48
48 Population 500 Heroin Addicts Sample 100 Heroin Addicts 10 Weeks 21 Heroin Addicts Tested Negative for Heroin Trial 1 Making Group Comparisons and Identifying Associations
49
49 Bupe Tested Positive for Heroin Total 1002179 Tested Negative for Heroin Trial 1 Making Group Comparisons and Identifying Associations Teach Epidemiology
50
50 When you can measure what you are speaking about, and express it in numbers, you know something about it. Lord Kelvin But when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind. Making Group Comparisons and Identifying Associations Teach Epidemiology
51
51 A measure of how often an outcome occurs in a defined population in a defined period of time. It consists of a numerator and a denominator. Risk The numerator is the number of people in the population or sample who experienced the outcome and the denominator is the total number of people in the population or sample. Population / Sample Outcome Denominator Numerator Making Group Comparisons and Identifying Associations Teach Epidemiology
52
52 … the risk of a negative heroin test was 21 / 100 in a 10-week period 21 tested negative for heroin 100 study subjects Numerator Denominator Risk Making Group Comparisons and Identifying Associations Teach Epidemiology
53
53 A measure of how often an outcome occurs in a defined group of people in a defined period of time. The likelihood of an outcome occurring. Risk / Rate Making Group Comparisons and Identifying Associations Teach Epidemiology
54
54 Trial 1 Bupe Tested Positive for Heroin 1002179 Tested Negative for Heroin 21 100 or 21 % Calculating Risk Risk of Negative Heroin Test Total Making Group Comparisons and Identifying Associations Teach Epidemiology
55
55 Process of predicting from what is observed in a sample to what is true for the entire population. Inference Making Group Comparisons and Identifying Associations Teach Epidemiology
56
56 Trial 1 What does this tell you about the hypothesis? Buprenorphine will stop heroin addicts from using heroin. Inference Probe Bupe Tested Positive for Heroin 1002179 Tested Negative for Heroin 21 100 or 21 % Risk of Negative Heroin Test Total Making Group Comparisons and Identifying Associations Teach Epidemiology
57
57 People who participate in a trial, but do not get the treatment. People whose results are compared to the group that was treated. Control Group Making Group Comparisons and Identifying Associations Teach Epidemiology
58
58 21 100 or 21 % 1007921 Tested Positive for Heroin Tested Negative for Heroin Bupe Control Group Extend and label the table to include a control group. Risk of Negative Heroin Test Total Making Group Comparisons and Identifying Associations Teach Epidemiology
59
59 100 ? or ? % No Bupe Control Group Making Group Comparisons 21 100 or 21 % 1007921 Tested Positive for Heroin Tested Negative for Heroin Bupe Risk of Negative Heroin Test Total Making Group Comparisons and Identifying Associations Teach Epidemiology
60
60 100 ? or ? % No Bupe Making Group Comparisons 21 100 or 21 % 1007921 Tested Positive for Heroin Tested Negative for Heroin Bupe ExposureExposure Outcome / Disease ab cd Risk of Negative Heroin Test Total Making Group Comparisons and Identifying Associations Teach Epidemiology
61
61 21 100 or 21 % Total 1007921 Bupe 100 ? or ? % No Bupe Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Making Group Comparisons and Identifying Associations Teach Epidemiology
62
62 A cross-classification of data where categories of one variable are presented in rows and categories of another variable are presented in columns The simplest contingency table is the 2x2 table. Contingency Table Making Group Comparisons and Identifying Associations Teach Epidemiology
63
63 Population 500 Heroin Addicts Sample 100 Heroin Addicts 10 Weeks 21 Heroin Addicts Tested Negative for Heroin Trial 1 Making Group Comparisons and Identifying Associations
64
64 Trial 2 Total ? 100 ? % a b c d Bupe Tested Negative for Heroin Tested Positive for Heroin No Bupe100 ? ? % Risk of Negative Heroin Test Making Group Comparisons and Identifying Associations Teach Epidemiology
65
65 E Assigned E O O O O Making Group Comparisons and Identifying Associations Volunteer Heroin Addicts Teach Epidemiology
66
66 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Probe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Making Group Comparisons and Identifying Associations Teach Epidemiology
67
67 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or Making Group Comparisons and Identifying Associations Teach Epidemiology
68
68 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or Inference: Process of predicting from what is observed in a sample to what is occurring in the entire population Making Group Comparisons and Identifying Associations Teach Epidemiology
69
69 When you can measure what you are speaking about, and express it in numbers, you know something about it. Lord Kelvin But when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind. Making Group Comparisons and Identifying Associations Teach Epidemiology
70
70 The value obtained by dividing one quantity by another Ratio Making Group Comparisons and Identifying Associations Teach Epidemiology
71
71 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or Ratio: The value obtained by dividing one quantity by another Risk Ratio: The ratio of two risks 1 Risk Ratio Making Group Comparisons and Identifying Associations Teach Epidemiology
72
72 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or Ratio: The value obtained by dividing one quantity by another Risk Ratio: The ratio of two risks 1 Risk Ratio Create a formula a a + b c c + d Making Group Comparisons and Identifying Associations Teach Epidemiology
73
73 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or 1 Risk Ratio Relative Risk: The ratio of the risk of an outcome among the exposed to the risk of the outcome among the unexposed. Relative Risk Making Group Comparisons and Identifying Associations Teach Epidemiology
74
74 21 100 21% 2179100 or a b c d Bupe Trial 2 No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 21 100 21% 2179100 or 1 Risk Ratio Relative Risk Inference: Process of predicting from what is observed in a sample to what is occurring in the entire population The inference here is that there is no effect of Buprenorphine Making Group Comparisons and Identifying Associations Teach Epidemiology
75
75 Trial 3 ? 100 ? % 100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test ? 100 ? % 100 or Making Group Comparisons and Identifying Associations Teach Epidemiology
76
76 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
77
77 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 62 100 62% 6238100 or Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
78
78 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 62 100 62% 6238100 or Inference: Process of predicting from what is observed in a sample to what is occurring in the entire population Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
79
79 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 62 100 62% 6238100 or Relative Risk Relative Risk: The ratio of the risk of an outcome among the exposed to the risk of the outcome among the unexposed. 0.34 Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
80
80 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 62 100 62% 6238100 or Relative Risk 0.34 The heroin addicts who received Bupe were ___ times as likely to test negative for heroin as those who did not receive Bupe. 0.34 Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
81
81 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 62 100 62% 6238100 or Relative Risk 0.34 Inference: Process of predicting from what is observed in a sample to what is occurring in the entire population. Trial 3 Making Group Comparisons and Identifying Associations Teach Epidemiology
82
82 Trial 4 ? 100 ? % 100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test ? 100 ? % 100 or Making Group Comparisons and Identifying Associations Teach Epidemiology
83
83 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
84
84 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 6 100 6% 694100 or Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
85
85 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 6 100 6% 694100 or Relative Risk Relative Risk: The ratio of the risk of an outcome among the exposed to the risk of the outcome among the unexposed. 3.5 Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
86
86 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 6 100 6% 694100 or Relative Risk 3.5 The heroin addicts who received Bupe were ___ times as likely to test negative for heroin as those who did not receive Bupe. 3.5 Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
87
87 21 100 21% 2179100 or a b c d Bupe No Bupe Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test 6 100 6% 694100 or Relative Risk 3.5 Inference: Process of predicting from what is observed in a sample to what is occurring in the entire population. Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
88
88 21 100 21% 2179100 or Bupe Trial 1 Total Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test What do the results tell us about the hypothesis that Buprenorphine will stop heroin addicts from using heroin? Nothing Making Group Comparisons and Identifying Associations Teach Epidemiology
89
89 Trial 1 Trial 2 Trial 3 Trial 4 Making Group Comparisons and Identifying Associations Teach Epidemiology
90
90 Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 Making Group Comparisons and Identifying Associations Teach Epidemiology
91
91 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 Making Group Comparisons and Identifying Associations Teach Epidemiology
92
92 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 Making Group Comparisons and Identifying Associations Teach Epidemiology
93
93 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 1 Bupe is not associated with having a negative test for heroin. Making Group Comparisons and Identifying Associations Teach Epidemiology
94
94 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 Bupe is not associated with having a negative test for heroin. 1 1006238 90 or 62% 62 100 Bupe is associated with having a positive test for heroin!.34 Making Group Comparisons and Identifying Associations Teach Epidemiology
95
95 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 Bupe is not associated with having a negative test for heroin. 1 1006238 90 or 62% 62 100 Bupe is associated with having a positive test for heroin!.34 100694 90 or 6% 6 100 Bupe is associated with having a negative test for heroin. 3.5 Making Group Comparisons and Identifying Associations Teach Epidemiology
96
96 Risk of Negative Heroin Test Nothing Bupe Total Trial 1 Trial 2 Trial 3 Trial 4 Bupe No Bupe Bupe No Bupe Bupe Total Relative Risk No Bupe Total Relative Risk Total Tested Negative for Heroin Tested Positive for Heroin Relative Risk Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin Risk of Negative Heroin Test Tested Negative for Heroin Tested Positive for Heroin 1002179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 2179 90 or 21% 21 100 Bupe is not associated with having a negative test for heroin. 1 1006238 90 or 62% 62 100 Bupe is associated with having a positive test for heroin!.34 100694 90 or 6% 6 100 Bupe is associated with having a negative test for heroin. 3.5 Nothing Compared to what? Making Group Comparisons and Identifying Associations Teach Epidemiology
97
97 Buprenorphine Buprenorphine & Naloxone Placebo Making Group Comparisons and Identifying Associations Teach Epidemiology Handout
98
98 National Research Council, Learning and Understanding Teach Epidemiology Enduring Epidemiological Understandings Knowledge that “… is connected and organized, and … ‘conditionalized’ to specify the context in which it is applicable.”
99
99 Time Check 10:30 AM
100
100
101
101 Teach Epidemiology
102
102 Time Check 10:45 AM
103
103
104
104 Teach Epidemiology
105
105 Suicide Higher in Areas with Guns Smoking Linked to Youth Eating Disorders Snacks Key to Kids’ TV- Linked Obesity: China Study Family Meals Are Good for Mental Health Lack of High School Diploma Tied to US Death Rate Study Links Spanking to Aggression Breakfast Each Day May Keep Colds Away Study Concludes: Movies Influence Youth Smoking Study Links Iron Deficiency to Math Scores Kids Who Watch R-Rated Movies More Likely to Drink, Smoke Pollution Linked with Birth Defects in US Study Depressed Teens More Likely to Smoke In the News
106
106 Total ab dc 2 x 2 Table Suicide Higher in Areas with Guns
107
107 Total ab dc People who are exposed ab 2 x 2 Table Suicide Higher in Areas with Guns Areas with Guns No Suicide Suicide Areas without Guns
108
108 ab dc 2 x 2 Table Total Kids Who Watch R-Rated Movies More Likely to Drink, Smoke
109
109 ab dc 2 x 2 Table R-Rated Movies Total Drink & Smoke Kids Who Watch R-Rated Movies More Likely to Drink, Smoke No Drink & Smoke No R-Rated Movies
110
110 ab dc People who are exposed and have the outcome a 2 x 2 Table R-Rated Movies Total Drink & Smoke Kids Who Watch R-Rated Movies More Likely to Drink, Smoke No Drink & Smoke No R-Rated Movies
111
111 ab dc 2 x 2 Table Family Meals Are Good for Mental Health Total
112
112 ab dc 2 x 2 Table Family Meals Are Good for Mental Health Family Meals Total Mental Health No Mental Health No Family Meals
113
113 ab dc People who are not exposed and do not have the outcome d 2 x 2 Table Family Meals Are Good for Mental Health Family Meals Total Mental Health No Mental Health No Family Meals
114
114 ab dc 2 x 2 Table Study Links Iron Deficiency to Math Scores Total
115
115 ab dc 2 x 2 Table Study Links Iron Deficiency to Math Scores Iron Deficiency Poor Math Scores No Iron Deficiency Good Math Scores Total
116
116 ab dc People who do not have the outcome and are not exposed d 2 x 2 Table Study Links Iron Deficiency to Math Scores Iron Deficiency Poor Math Scores No Iron Deficiency Good Math Scores Total
117
117 ab dc 2 x 2 Table Pollution Linked with Birth Defects in US Study Total
118
118 ab dc 2 x 2 Table Pollution Linked with Birth Defects in US Study Pollution Birth Defects No Pollution No Birth Defects Total
119
119 ab dc People who are not exposed dc 2 x 2 Table Pollution Linked with Birth Defects in US Study Pollution Birth Defects No Pollution No Birth Defects Total
120
120 ab dc 2 x 2 Table Depressed Teens More Likely to Smoke Total
121
121 ab dc People who do not have the outcome d b 2 x 2 Table Depressed Teens More Likely to Smoke Depression Smoke No Depression No Smoke Total
122
122 ab dc 2 x 2 Table Smoking Linked to Youth Eating Disorders Total
123
123 ab dc 2 x 2 Table Smoking Linked to Youth Eating Disorders Smoke Eating Disorders No Smoke No Eating Disorders Total
124
124 ab dc People who are exposed and do not have the outcome b 2 x 2 Table Smoking Linked to Youth Eating Disorders Smoke Eating Disorders No Smoke No Eating Disorders Total
125
125 ab dc 2 x 2 Table Total Study Links Spanking to Aggression
126
126 ab dc People who have the outcome a c 2 x 2 Table Study Links Spanking to Aggression Spanking Aggression No Spanking Total No Aggression
127
127 ab dc 2 x 2 Table Total Snacks Key to Kids’ TV-Linked Obesity – China Study
128
128 ab dc 2 x 2 Table Snacks Key to Kids’ TV-Linked Obesity – China Study Snacks Obesity No Snacks No Obesity Total People who are not exposed and have the outcome c
129
129
130
130 National Research Council, Learning and Understanding Teach Epidemiology Enduring Epidemiological Understandings Knowledge that “… is connected and organized, and … ‘conditionalized’ to specify the context in which it is applicable.”
131
131 Laboratory Teach Epidemiology Making Group Comparisons and Identifying Associations
132
132 Laboratory Teach Epidemiology Making Group Comparisons and Identifying Associations
133
133 Naturally occurring circumstances in which groups of people within a population have been exposed to different levels of the hypothesized cause of an outcome. Natural Experiment Teach Epidemiology Making Group Comparisons and Identifying Associations
134
134 An epidemiologic study of a natural experiment in which the investigator is not involved in the intervention other than to record, classify, count, and statistically analyze results. Observational Study Teach Epidemiology Making Group Comparisons and Identifying Associations
135
135 An epidemiologic experiment in which subjects are assigned into groups to receive or not receive a hypothesized beneficial intervention. Controlled Trial Teach Epidemiology Making Group Comparisons and Identifying Associations
136
136 Buprenorphine Buprenorphine will stop heroin addicts from using heroin. Teach Epidemiology Making Group Comparisons and Identifying Associations
137
137 Naturally occurring circumstances in which groups of people within a population have been exposed to different levels of the hypothesized cause of an outcome. Observational Study of a Natural Experiment Epidemiologic studies of natural experiments in which the investigator is not involved in the intervention other than to record, classify, count, and statistically analyze results. Teach Epidemiology Making Group Comparisons and Identifying Associations
138
Laboratory Teach Epidemiology Making Group Comparisons and Identifying Associations
139
139 Making Group Comparisons and Identifying Associations Teach Epidemiology
140
140 Making Group Comparisons and Identifying Associations Teach Epidemiology
141
141 Stephen Jay Gould (survivor of abdominal mesothelioma) Absolutely nothing in the available arsenal of anti-emetics worked at all. I was miserable and came to dread the frequent treatments with an almost perverse intensity. I had heard that marijuana often worked well against nausea. I was reluctant to try it because I had never smoked any substance habitually (and didn’t even know how to inhale). Moreover, I had tried marijuana twice (in the 1960s) … and had hated it …. Marijuana worked like a charm …. The sheer bliss of not experiencing nausea - and not having to fear it for all the days intervening between treatments - was the greatest boost I received in all my year of treatment, and surely the most important effect upon my eventual cure. Making Group Comparisons and Identifying Associations Teach Epidemiology
142
142 A particular or detached incident or fact of an interesting nature; a biographical incident or fragment; a single passage of private life. Anecdote Making Group Comparisons and Identifying Associations Teach Epidemiology
143
143 Science Transforming Anecdote to Science Making Group Comparisons and Identifying Associations Teach Epidemiology Anecdote
144
144 Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People - E Random Assignment E DZ Controlled Trial Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People - E E DZ Cohort Study Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Case-Control Study - DZ E E E E Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Cross-Sectional Study - E E DZ Making Group Comparisons and Identifying Associations Teach Epidemiology
145
145 Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People - E Random Assignment E DZ Controlled Trial Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People - E E DZ Cohort Study Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Case-Control Study - DZ E E E E Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Cross-Sectional Study - E E DZ d b c a Making Group Comparisons and Identifying Associations Teach Epidemiology
146
The goal of every epidemiological study is to harvest valid and precise information about the relationship between an exposure and a disease in a population. The various study designs merely represent different ways of harvesting this information. Essentials in Epidemiology in Public Health Ann Aschengrau and George R. Seage III Making Group Comparisons and Identifying Associations Teach Epidemiology
147
147 Time Check 11:30 AM
148
148
149
149 Teach Epidemiology
150
150 Time Check 12:30 PM
151
151
152
152 Teach Epidemiology
153
153
154
The Journey Detectives in the Classroom - Investigation 2-6: The Journey
155
Analogy Detectives in the Classroom - Investigation 2-6: The Journey
156
Epi Talk Study Design Epi Talk Procedures and methods, established beforehand, that are followed by the investigator conducting the study. Detectives in the Classroom - Investigation 2-6: The Journey
157
Timing When are the passengers identified as exposed or unexposed? E When are the passengers identified as sick or not sick? DZ Timing When does the epidemiologist start to observe the journey? - Detectives in the Classroom - Investigation 2-6: The Journey
158
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ E DZ Label the Train Tracks - Detectives in the Classroom - Investigation 2-6: The Journey
159
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Study Design: E DZ Label the Train Tracks - Controlled Trial Detectives in the Classroom - Investigation 2-6: The Journey
160
Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People Controlled Trial Flow Diagram - Healthy People E Random Assignment E DZ Detectives in the Classroom - Investigation 2-6: The Journey
161
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Study Design: Label the Train Tracks Cohort Study Detectives in the Classroom - Investigation 2-6: The Journey
162
Cohort Study Just as in the controlled trial, the epidemiologist is also on the train during the entire journey. But there is an important difference. The epidemiologist is not telling passengers what to do. Rather, the epidemiologist is just observing them and counting. Passengers are not being told to have or not have an exposure, they are just living their normal lives. The epidemiologist, on the ride for the whole journey, just keeps observing everyone’s exposures and whether or not they develop the disease during the journey. Label the Train Tracks Detectives in the Classroom - Investigation 2-6: The Journey
163
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ E DZ Label the Train Tracks - Study Design: Cohort Study Detectives in the Classroom - Investigation 2-6: The Journey
164
Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People Cohort Study Flow Diagram - Healthy People E E DZ Detectives in the Classroom - Investigation 2-6: The Journey
165
Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People Cohort Study Flow Diagram - Healthy People E E DZ Controlled Trial Detectives in the Classroom - Investigation 2-6: The Journey
166
Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Healthy People Cohort Study Flow Diagram - Healthy People E E DZ Controlled Trial Random Assignment Detectives in the Classroom - Investigation 2-6: The Journey
167
Review Observational Studies Epi Talk Epidemiologic studies of natural experiments in which the investigator is not involved in the intervention other than to record, classify, count, and statistically analyze results. Detectives in the Classroom - Investigation 2-6: The Journey
168
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Label the Train Tracks Study Design: Case-Control Study Detectives in the Classroom - Investigation 2-6: The Journey
169
The epidemiologist is not on the journey. Rather, the epidemiologist is waiting at the train station at the end of the journey. As passengers get off the train, the epidemiologist selects sick passengers for the case group and selects passengers who are similar but not sick for the control group. The epidemiologist then asks each person in the case group and control group questions about their exposures during the train ride. The epidemiologist relies on passengers’ memories of their exposures that occurred during the train ride. Label the Train Tracks Case-Control Study Detectives in the Classroom - Investigation 2-6: The Journey
170
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ E DZ Label the Train Tracks - Study Design: Case-Control Study Detectives in the Classroom - Investigation 2-6: The Journey
171
Case-Control Study Observational Study Flow Diagram Flow Diagram Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ DZ - E E E E Detectives in the Classroom - Investigation 2-6: The Journey
172
Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Label the Train Tracks Study Design: Cross-Sectional Study Detectives in the Classroom - Investigation 2-6: The Journey
173
The epidemiologist, who has not been on the journey, stops the train somewhere during the trip (kind of like a train robbery) and takes a “snapshot” of all the passengers by asking them whether or not they have the exposure and whether or not they have the disease. Then the epidemiologist leaves the train and goes home to analyze the data from that particular day. The journey continues without the epidemiologist. Label the Train Tracks Cross-Sectional Study Detectives in the Classroom - Investigation 2-6: The Journey
174
E DZ Time +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Label the Train Tracks - Study Design: Cross-Sectional Study Detectives in the Classroom - Investigation 2-6: The Journey
175
Cross-Sectional Study Observational Study Flow Diagram Flow Diagram Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ E E - DZ Detectives in the Classroom - Investigation 2-6: The Journey
176
Epi Talk Controlled Trial Epi Talk An epidemiologic experiment in which subjects are assigned into groups to receive or not receive a hypothesized beneficial intervention. Detectives in the Classroom - Investigation 2-6: The Journey
177
Epi Talk Cohort Study Epi Talk An analytical epidemiological study design in which the investigator selects a group of exposed individuals and a group of unexposed individuals and follows both groups to compare the frequency with which the disease occurs in each group. Detectives in the Classroom - Investigation 2-6: The Journey
178
Epi Talk Case-Control Study Epi Talk An analytical epidemiological study design in which the investigator selects a group of individuals with a disease (cases) and a group of similar individuals without the disease (controls) and compares the frequency with which an exposure occurred in the cases versus the controls. Detectives in the Classroom - Investigation 2-6: The Journey
179
Epi Talk Cross-Sectional Study Epi Talk An analytical epidemiological study design in which the investigator selects a group of individuals and determines the presence or absence of a disease and the presence or absence of an exposure at the same time. Detectives in the Classroom - Investigation 2-6: The Journey
180
180
181
181
182
182 Healthy People - E E O O O O Cohort Study
183
183 Handouts
184
184
185
185 http://www.nationalchildrensstudy.gov/Pages/default.aspx
186
186
187
187
188
188 Science Transforming Anecdote to Science Making Group Comparisons and Identifying Associations Anecdote
189
189
190
190 Healthy People Flow Diagram Randomized Controlled Trial - Healthy People E Random Assignment E O O O O
191
191 Healthy People Flow Diagram - Healthy People E E O O O O Cohort Study Observational Study
192
192 http://abcnews.go.com/US/mystery-illness-hits-22-students-houston-texas-high/story?id=14888448#.Traba3Ltl8N Handouts
193
193 Case-Control Study O - O E E E E
194
194 http://www.youtube.com/watch?v=Xjgu2gYs2UQ
195
195 http://abcnews.go.com/US/mystery-illness-hits-22-students-houston-texas-high/story?id=14888448#.Traba3Ltl8N Check Notes
196
196
197
197
198
Teacher Note: Enduring Epidemiological Understandings for the Epidemiology and the Energy Balance Equation Curriculum 1.Health and disease are not distributed haphazardly in a population. There are patterns to their occurrence that can be identified through surveillance. Analysis of the patterns of health and disease distribution can provide clues for formulating hypotheses about their possible causes. 2.Causal hypotheses can be tested by conducting investigations of the exposures and outcomes of selected groups of people as they go about their lives. Information from these observational studies can be used to determine if an exposure and an outcome are associated. Because observational studies are complicated by factors not controlled by the observer, other explanations also must be considered. 198
199
Teacher Note: Authentic Assessment for Module 2 of the Epidemiology and the Energy Balance Equation Curriculum 199 Students will conduct, analyze, and interpret observational, cross- sectional studies among students in their class and then among students outside their class. Working in teams, students will have the opportunity to demonstrate their abilities to select a reasonable hypothesis of interest to them, design study questions about exposure and outcome, obtain informed consent, collect and manage data, calculate and compare prevalence rates, make accurate statements about whether their data support that hypothesis, and consider alternate explanations for what they observed. Reporting of results will be required, such as a written report, an item for the school newspaper, or an oral presentation or poster for students, teachers, and/or parents. Specific performance criteria will be used to help ensure that the experiences allow a genuine, realistic, and fair assessment of students’ comprehension of the Module 2 Enduring Epidemiological Understanding.
200
200 Teacher Note: Photos of Worksheets for Lesson 2-3 2-3b 2-3a 2-3c 2-3d
201
Start of Lesson 2-3 (estimate 2 class periods) 201
202
202 Big Ideas in Lesson 2-2 The cross-sectional design is an observational study of a natural experiment This design is relatively quick and simple, asking individuals about exposure and outcome at one point in time After the prevalence is calculated for the group with the exposure, the next question is “compared to what?” The “compared to what” consists of prevalence for the unexposed “controls” Dividing one prevalence by the other produces the prevalence ratio; it tells us if/how the exposure and outcome are associated Because exposure and outcome are measured at the same point in time, it is usually not possible to determine the time order of the exposure and the outcome (which came first) and as such, the association may not be interpretable Review
203
Overview of Lesson 2-3 203
204
2-3a Checklist - Study Planning Components and Expectations 2-3 Study Hypothesis - Statement of a hypothesized association between an exposure and an outcome 2-3 Study Variables - Developing questions about exposure and outcome, and additional questions about participants 2-3 Questionnaire - Preparing a one-page sheet that study participants will fill out (typed and copies made) 2-4 Draft Informed Consent Script - Preparing a script to be read to possible study participants (typed and copies made) 2-5 Plans for Study Conduct – Having assignments for study day 204 Notebook Study
205
Part of 2-3a Expectations for Successful Completion of Activities in Lesson 2-3 205 Notebook Study #Study Plan Component Met Some- what Met Not Met 2-3 Study Hypothesis - Statement of a hypothesized association between an exposure and an outcome 1) Stated clearly; 2) makes sense at face value; and 3) is feasible to study in a school setting □□ □ 2-3 Study Variables - Developing questions about exposure and outcome 1) Clear questions that will mean the same thing to anyone who reads it; 2) a good description of what you are trying to measure; 3) a good understanding of challenges in measurement; and 4) an awareness of other information about study participants that will help in understanding study results 2-3 Questionnaire - Preparing a one-page sheet that study participants will fill out (typed and copies made) Format of the survey that is user-friendly and clear in presenting questions and answer options and instructions
206
206 An educated guess An unproven idea, based on observation or reasoning, that can be supported or refuted through investigation A tentative explanation Hypotheses
207
Hypotheses? 207
208
Hypotheses? 208
209
209 Tips Your hypothesis statement should state the hypothesized relationship between an exposure variable and an outcome variable, including the direction expected. Make sure that the hypothesis you choose is of genuine interest to you, because you will be spending your time and energy exploring it. Your stated hypothesis MUST NOT require the collection of any information that might be considered embarrassing, sensitive, or illegal. The hypothesis needs to be related to nutrition and/or physical activity.
210
Eat school cafeteria food Regularly watch TV Have a sedentary lifestyle Have a high-fat diet Take multivitamins Eat breakfast Have perception of overweight Have good academic performance Regularly play computer games Eat junk food every day Examples of Variables to Use in a Hypothesis Have a low-fat diet Regularly exercise Participate in a team sport Eat fruits and vegetables Drink high calorie drinks Drink diet soda Walk to school Get a good night’s rest Other ? ? ? 210
211
Some variables can be an exposure or an outcome When is “eating more fruits and vegetables” an exposure? When is “eating more fruits and vegetables” an outcome? Examples of Hypotheses: - People who eat more fruits and vegetables take more multivitamins - People who rarely watch TV are more likely to eat fruits and vegetables When is “having more physical activity” an exposure? When is “having more physical activity” an outcome? Examples of Hypotheses: - Physical activity is associated with a longer night’s sleep - People with high academic performance are more likely to also have more physical activity 211
212
212 2-3b Notebook Study Study Hypothesis Why is your study team interested in testing this hypothesis? Discuss the reason(s) your team thinks it will be possible to test this hypothesis in your class and school. “X is associated with Y” “People with X are more likely to have Y” “People with X have higher, or more Y” How do I state a hypothesis?
213
Eat school cafeteria food Regularly watch TV Have a sedentary lifestyle Have a high-fat diet Take multivitamins Eat breakfast Have perception of overweight Have good academic performance Regularly play computer games Eat junk food every day Have a low-fat diet Regularly exercise Participate in a team sport Eat fruits and vegetables Drink high calorie drinks Drink diet soda Walk to school Get a good night’s rest Other ? ? ? 213 2-3b Notebook Study Study Hypothesis
214
A few examples of hypotheses to test Students who drink caffeinated drinks do more homework after school. Students who drink caffeinated drinks get less sleep. Healthy eating (at least 2 servings of fruit and vegetables a day) results in better grades (“doing well in school. Students that regularly eat vegetables have fewer periods of illness (24 hours or more of flu/cold symptoms). Students who eat breakfast have fewer colds and therefore have fewer absences from school. A healthy breakfast is associated with playing in an organized sport. Students who eat dinner with their family more often get better grades. Students who skip lunch will eat more snacks. People who eat more fruits and vegetables take more multivitamins. Drinking more water is associated with eating more fruits and vegetables. Students who drink more sweetened drinks are more likely to eat unhealthy snacks. Drinking at least 2 cans or a 20 ounce bottle of non-diet soda per day leads to a crash (feeling tired). 214 OPTIONAL SLIDE TO SHOW STUDENTS
215
Students who have one or more cats or dogs are more physically active. Students who have one or more cats or dogs have more school absences due to colds. Receiving a daily, weekly, or monthly allowance is related to eating junk food/unhealthy food more than twice a day. Students who chew gum eat fewer snacks. Students who listen to an IPOD are more likely to participate in physical activity. Students who text more are less physically active. Watching more TV is associated with having lower stress levels. Students who watch TV eat more snacks. Students who regularly play video games eat more snacks. Students who play regular video games (not active) eat more junk food. Playing active video games is related to getting better grades. Student athletes, on average, get more sleep than students who do not participate in a sport. 215 OPTIONAL SLIDE TO SHOW STUDENTS A few examples of hypotheses to test
216
Students who participate in sports are more satisfied with their lives Physical activity is associated with eating less junk food. People who participate in a team sport are more likely to eat fruits and vegetables. Physically active students place greater weight on the importance of a healthy lifestyle. Regular exercise is related to higher academic performance. Students who get 8 or more hours of sleep on average have higher academic performance. Students who sleep <8 hours a night eat more often than those who get at least 8 hours of sleep. Students who have less parental supervision are more likely to watch TV. Students who have less parental supervision eat more junk food for after school snacks. High academic performance is associated with more physical activity. High academic performance is associated with a healthy diet. 216 OPTIONAL SLIDE TO SHOW STUDENTS A few examples of hypotheses to test
217
217 Possible break point between class periods
218
More Information about CHIS Study Theresa A. Hastert, Susan H. Babey. School lunch source and adolescent dietary behavior. Prevention of Chronic Diseases 2009, Vol 6 (4). http://www.cdc.gov/pcd/issues/2009/oct/08_0182.htm 218
219
Review: “Criteria for a Good Question” It should be clear and unambiguous, written so that its intended audience understands it. It should mean the same thing to everyone who reads it. The answer options must categorize and cover the entire range of possible behavior (from complete absence of the behavior to a maximum amount of the behavior). The time period to consider when answering a particular question must be appropriate (long or short enough) to capture the frequency of behavior desired (depending on the information desired and the type of behavior). 219
220
220 Exposure Question During the school year, about how many times a week do you usually bring your own lunch to school from home? 0 1 2 3 4 5
221
221 Outcome Questions TOPICQUESTION Fruit? Vegetables? Fast food? Soda? Fried potatoes? High-sugar foods?
222
222 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? Vegetables? Fast food? Soda? Fried potatoes? High-sugar foods? Outcome Questions
223
223 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? VegetablesYesterday, how many servings of vegetables, like corn, green beans, green salad or other vegetables did you eat? Fast food? Soda? Fried potatoes? High-sugar foods? Outcome Questions
224
224 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? VegetablesYesterday, how many servings of vegetables, like corn, green beans, green salad or other vegetables did you eat? Fast foodYesterday, how many times did you eat fast food? Soda? Fried potatoes? High-sugar foods? Outcome Questions
225
225 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? VegetablesYesterday, how many servings of vegetables, like corn, green beans, green salad or other vegetables did you eat? Fast foodYesterday, how many times did you eat fast food? SodaYesterday, how many glasses or cans of soda, such as Coke, or other sweetened drinks, such as fruit punch or Sunny Delight did you drink? Do not count diet drinks. Fried potatoes? High-sugar foods? Outcome Questions
226
226 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? VegetablesYesterday, how many servings of vegetables, like corn, green beans, green salad or other vegetables did you eat? Fast foodYesterday, how many times did you eat fast food? SodaYesterday, how many glasses or cans of soda, such as Coke, or other sweetened drinks, such as fruit punch or Sunny Delight did you drink? Do not count diet drinks. Fried potatoesYesterday, how many servings of French fries, home fries, or hash browns did you eat? High-sugar foods? Outcome Questions
227
227 TOPICQUESTION FruitYesterday, how many servings of fruit, such as an apple or a banana, did you eat? VegetablesYesterday, how many servings of vegetables, like corn, green beans, green salad or other vegetables did you eat? Fast foodYesterday, how many times did you eat fast food? SodaYesterday, how many glasses or cans of soda, such as Coke, or other sweetened drinks, such as fruit punch or Sunny Delight did you drink? Do not count diet drinks. Fried potatoesYesterday, how many servings of French fries, home fries, or hash browns did you eat? High-sugar foodsYesterday, how many servings of high-sugar foods, such as cookies, candy, doughnuts, pastries, cake or popsicles did you eat? Outcome Questions
228
Questions for your Cross-Sectional Studies One question must obtain information about the exposure in your hypothesis and the other question must obtain information about the outcome in your hypothesis. The study information on exposure and outcome must fit into a 2x2 table. A “yes/no” question will fit and is recommended. If using a multiple choice question, you will need a predetermined “cut point” so there is a “higher/lower” range to fit into the 2x2 table. 228
229
Yes Exposure Total No Exposure ab cd Yes Outcome No Outcome The 2x2 table Exposure and Outcome Distributions Among Individuals in a Study Population Optional: Use as needed for review of 2x2 tables and necessity for a question about exposure and a question about outcome 229
230
2-3c Study Variables: Questions About Exposure and Outcome and Additional Questions 230 Notebook Study How should we ask about eating a healthy breakfast?
231
“Criteria for a Good Question” It should be clear and unambiguous, written so that its intended audience understands it. It should mean the same thing to everyone who reads it. The answer options must categorize and cover the entire range of possible behavior (from complete absence of the behavior to a maximum amount of the behavior). The time period to consider when answering a particular question must be appropriate (long or short enough) to capture the frequency of behavior desired (depending on the information desired and the type of behavior). 231
232
2-3c Item 5 - Labeling a 2x2 Table 232 Notebook Study 2x2 Table Fill in the two boxes in the table below, to show how your exposure and outcome variables will be analyzed in a contingency table in order to test your hypothesis. (Note: if you plan to use multiple choice questions for your exposure and/or outcome, determine cut points for the data so that you can fill in the contingency table below.)
233
233 2-3c Item 6 – Additional Questions Notebook Study Think about what other information about students in your study would be interesting to know, in terms of your hypothesis. (Hint: perhaps gender would be one of these) In the space below, write any additional questions for your questionnaire that will gather information about these other characteristics of your study subjects.. Should we ask about gender? Questions to Gather Additional Information on Participants
234
Break Between Classes 234
235
235 2-3d Sample Questionnaire for for Cross-Sectional Study Notebook Study Thank you for your participation in this survey. Please answer the questions below by circling one choice for each question. When you are finished, fold this paper in half and follow instructions for handing in your questionnaire. Remember: Do not write your name anywhere on this paper. Study Questions: (Circle one answer for each question) 1. During the past month, did you usually eat 2 or more servings of fruits/vegetables per day? Yes No 2. In the last semester that you have completed, did you have a grade average of A or B? Yes No 3. What is your gender? Male Female 4. What grade are you in? 6th grade 7th grade 8th grade
236
236 Type your questionnaire Make enough copies for all potential study participants
237
237 Big Ideas in Lesson 2-3 A good study plan includes careful thought about choice of exposure and outcome variables and high-quality questions to measure them Additional questions about other characteristics of participants can be asked in order to better understand study results A well-planned study has a user-friendly questionnaire to administer to participants Re-Cap
238
238 Time Check 2:15 PM
239
239
240
240 Teach Epidemiology
241
Teachers Team-Teaching Teachers (TTTT) News Item Team leads other workshop participants in the analysis of a news item from an epidemiological perspective. 1
242
Teach Epidemiology Teachers Team-Teaching Teachers (TTTT) News Item Team leads other workshop participants in the analysis of a news item from an epidemiological perspective. 2
243
Teach Epidemiology Teachers Team-Teaching Teachers (TTTT) Existing Lesson Team leads other workshop participants in a portion of a selected existing epidemiological lesson. 3
244
Teach Epidemiology Teachers Team-Teaching Teachers (TTTT) Existing Lesson Team leads other workshop participants in a portion of a selected existing epidemiological lesson. 4
245
TTTT Rules 245 1.Teach epidemiology 2.As a group, create a 30-minute lesson during which we will develop a deeper understanding of an enduring epidemiological understanding. 3.Focus on the portion of the unit that is assigned. Use that portion of the unit as the starting point for creating your 30-minute lesson. 4.When teaching assume the foundational epidemiological knowledge from the preceding days of the workshop. 5.Try to get us to uncover the enduring epidemiological understanding. Try to only tell us something when absolutely necessary. 6.End each lesson by placing it in the context of the appropriate enduring epidemiological understanding. 7.Teach epidemiology. 8.After the lesson, metacognitate about your preparation for and teaching of the lesson. Teach Epidemiology
246
246 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Teachers Team-Teaching Teachers (TTTT)
247
247 Time Check 2:45 PM
248
248
249
249 Teach Epidemiology
250
250 Time Check 3:00 PM
251
251
252
252 Teach Epidemiology
253
253 Broadcast Studios Teach Epidemiology Tours
254
254 Time Check 4:00 PM
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.