1. Module 2 Introduction Context Content Area: Hypothesis Generation
Essential Question (Generic): What hypotheses might explain the distribution of health-related events or states?
Essential Question (Drug Abuse Specific): What hypotheses might explain drug abuse?
Enduring Epidemiological Understanding: Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population.
Synopsis
In Module 2, students explore how descriptive epidemiological information on person, place, and time (PPT) are used to generate hypotheses to explain “why” a health-related event or state has occurred. Students begin to uncover and develop the following epidemiological concepts and skills: evaluating PPT information; developing hypotheses to explain that distribution; understanding that there may be more than one credible hypothesis; and recognizing when a particular hypothesis does NOT explain the PPT information.
Lesson 2-1: Overview of PPT and What’s My Hypothesis?
Lesson 2-2: In the News
Lesson 2-3: Drug Abuse by “Person” Race / Ethnicity
Lesson 2-4: Drug Abuse by “Place” States in USA
Lesson 2-5: Drug Abuse by “Time” Boundary Effect
Each Lesson begins with an overview of the Module (there are 5 modules) and a listing of the Lessons in that Module.
DrugEpi 2-1 Overview of PPT and In the News

2. Module 2 - Hypothesis Generation
Lesson 2-1 Overview of PPT and What’s My Hypothesis?
Content
Introduction to using person, place, and time (PPT) to describe how a disease or other health-related condition is described in a population
Definition of “hypothesis” and explanation of how PPT is used to generate “educated guesses” based on observation
Example of a catastrophic event, and another example of an emerging disease, that illustrate the usefulness of PPT and provide practice for students to identify person, place, and time characteristics and generate hypotheses
Big Ideas
Person, place, and time (PPT) describes a disease or other health-related condition in terms of “who, where, and when”
Hypotheses that are suggested by PPT try to explain “why” a disease is distributed as it is
PPT information often leads to more than one reasonable hypothesis
Each Lesson then has a summary page that outlines the content and big ideas for that Lesson.
This project is supported by a Science Education Drug Abuse Partnership Award, Grant Number 1R24DA , from the National Institute on Drug Abuse, National Institutes of Health.
DrugEpi 2-1 Overview of PPT and In the News

3. Enduring Understandings
Where are we?
Essential Questions
Enduring Understandings 1.
How is this disease distributed?
Health-related conditions and behaviors are not distributed uniformly in a population. They have unique distributions that can be described by how they are distributed in terms of person, place, and time. 2.
What hypotheses might explain the distribution of disease?
Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population. 3.
Is there an association between the hypothesized cause and the disease?
Causal hypotheses can be tested by observing exposures and diseases of people as they go about their daily lives. Information from these observational studies can be used to make and compare rates and identify associations. 4.
Is the association causal?
Causation is only one explanation for an association between an exposure and a disease. Because observational studies are complicated by factors not controlled by the observer, other explanations also must be considered. 5.
What should be done when preventable causes of disease are found?
Policy decisions are based on more than the scientific evidence. Because of competing values - social, economic, ethical, environmental, cultural, and political factors may also be considered.
Teacher Note: This slide is inserted at the beginning of each lesson. Use it as needed to keep students oriented within the Module you are teaching and in relation to all five modules.
As needed . . .Remind students that this list includes the Enduring Understanding that accompanies each of the five Essential Questions.
The second Enduring Understanding is: Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population.
Note that the second Essential Question is: What hypotheses might explain the distribution of disease?
Lesson 2-1 introduces the concept of using person, place, and time to describe how a health-related condition is described in a population. Examples are used to give students practice in identifying person, place, and time characteristics.
DrugEpi 2-1 Overview of PPT and In the News

4. Review - Definition of Epidemiology
Remind students of the definition of epidemiology that they learned in the Orientation Lesson and in Module 1.
“… the study of the distribution and determinants of health-related states or events in specific populations and the application of this study to the control of health problems.”
DrugEpi 2-1 Overview of PPT and In the News

5. Review - the Descriptive Part of Epidemiology
Remind students that part of the definition of epidemiology is about descriptive epidemiology, which is “… the study of the distribution … of health-related states or events ….”
“… the study of the distribution and determinants of health-related states or events in specific populations and the application of this study to the control of health problems.”
DrugEpi 2-1 Overview of PPT and In the News

6. Descriptive Epidemiology
In Module 1, students learned how to describe the amount of health/disease conditions in populations.
In Module 2, students will become familiar with the other part of descriptive epidemiology, that of describing distributions by person, place and time. ). If we step back and observe how a disease or health-related condition is distributed, we realize that in the real world everyone does not get sick, in every place, at all times. For example, epidemiologists know that some people get sick, in some places, some of the time. And epidemiologists understand the importance of accurately describing that distribution.
Epidemiologic studies that are concerned with characterizing the amount and distribution of health and disease within a population.
DrugEpi 2-1 Overview of PPT and In the News

7. Descriptive Epidemiology
Person:
Place:
Time:
PPT Sheet
Who?
Where?
The description of people with a specific health condition (who), where they live (where), and the time frame involved (when), is the descriptive epidemiology of the disease or other health-related condition. This "who, where, when" idea is expressed by epidemiologists as Person, Place, and Time (PPT).
When?
DrugEpi 2-1 Overview of PPT and In the News

8. Descriptive Epidemiology
Person:
Place:
Time:
PPT Sheet
Illicit Drug Use
AIDS
Each disease or other health-related condition or behavior has its own unique descriptive epidemiology. For example, illicit drug use among young people varies by ethnic group. Early AIDS cases in the US were seen in large cities. Influenza epidemics are more likely to occur during the winter.
Once we know how a health condition is distributed, we can begin to speculate as to why it is distributed that way. For example, Why did these people get sick, in this place, at this time? In other words, epidemiologists have the ability to look at person, place, and time clues and make educated guesses to explain the PPT information.
For example, drug use may vary by ethnic group because of different availability and cost among types of illicit drugs and/or because of cultural factors. Because early AIDS cases were seen in large cities, we might formulate a hypothesis about the spread of an infectious agent in more densely populated areas. And because the flu is more likely to occur during the winter, we might speculate that exposure to cold weather causes the flu.
Influenza
DrugEpi 2-1 Overview of PPT and In the News

9. Definition of Hypotheses
An educated guess
An unproven idea, based on observation or reasoning, that can be supported or refuted through investigation
Tell students that the definition of hypothesis is an educated guess, or an unproven idea, based on an observation or reason, that can be supported or refuted through investigation.
How does this apply to descriptive epidemiology? Once we know how a disease is distributed, we can begin to speculate as to why it is distributed that way. Why did these people get sick, in this place, at this time? As we study these descriptive epidemiological clues, we can begin to identify some suspected causes and formulate hypotheses, or educated guesses, to try to explain why some people got sick and others did not.
It is important to remember that descriptive epidemiology may suggest several hypotheses and that even if a hypothesis is plausible (make sense in terms of PPT), it does not necessarily mean it is correct.
Another big idea to remember is that, in spite of the fact that hypotheses are often stated as if they are facts, they are not. They are educated guesses that may be tested with a scientific study. .
Next Slide
DrugEpi 2-1 Overview of PPT and In the News

10. Definition of Hypothesis
Insert slide in this lesson if you wish to give students context about hypothesis testing versus generating. This will be covered in Module 3
Generate
Descriptive Epidemiology
Test
Analytical Epidemiology
Hypothesis
An unproven idea, based on observation or reasoning, that can be supported or refuted through investigation
An educated guess
Remind students that they are learning from Essential Question 2 that clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population. This is illustrated on the left side of the slide.
In addition to formulating hypotheses, epidemiologists, disease detectives, also test their hypotheses. The hypothesis-testing part of epidemiology is called analytical epidemiology. This is illustrated on the right side of the slide. I
What ties these ideas together is the concept of Hypotheses - - descriptive epidemiology helps formulate hypotheses and analytical epidemiology helps test hypotheses. Hypothesis-testing will be covered in Module 3.
DrugEpi 2-1 Overview of PPT and In the News

11. Hypothesis Generation
2. What hypotheses might explain
the distribution of disease?
2. What hypotheses might explain
the distribution of drug abuse?
Point out to students that the essential question for Module 2 can be posed in a general way: “What hypotheses might explain the distribution of disease?” It can also be asked in a way that is specific to the content of these lessons: “What hypotheses might explain the distribution of drug abuse?”
In other words, general aspects of epidemiology are presented in this and other lessons, and epidemiological methods are also being applied specifically to the issue of drug abuse.
DrugEpi 2-1 Overview of PPT and In the News

12. Person, Place, and Time (PPT)
How is the disease or other health condition distributed?
Tell students that now that class will look more closely at the characteristics of person, place, and time.
Who?
Where?
When?
DrugEpi 2-1 Overview of PPT and In the News

13. Descriptive Epidemiology
Person (Who?)
Place (Where?)
Time (When?)
Sex
Age
Ethnicity
Occupation
Economic Group
Residence
Occupation
Being at Specific Events
Geographic Sites
Era
Year
Season
Day, Hour, etc.
Date of Onset
Duration
Tell students that this is a list of several PPT characteristics.
Note that among Person characteristics are traits of individuals (age, gender, ethnicity) as well as characteristics of individuals’ lives (jobs, economic status)
Place characteristics involve where a person is located, including where one lives and works, attendance at a specific event, and geographic sites.
Time can have many dimensions, ranging from large time periods (eras) to days and even hour in the day (such as timing of a food poisoning event).
Ask students if they can add any characteristics to these listings. (for example: Person -weight, heredity; Place - location in a building (e.g., World Trade Center); Time - holiday times, change over time)
DrugEpi 2-1 Overview of PPT and In the News

14. Practice int Hypothesis Generation
SES
Tell students that this table will be filled out with some descriptive epidemiology information.
Ask students which type of information this is, Person, Place or Time (Person characteristics of gender, adult versus child, socioeconomic status)
DrugEpi 2-1 Overview of PPT and In the News

15. Practice in Hypothesis Generation
SES
Explain to students that this distribution is of deaths incurred in an unusual incident.
After seeing the distribution, students will try to figure out what this incident was.
The first piece of information is that the number of persons who died is 2,206, and that this was 68.2% of the people present during this unusual incident.
DrugEpi 2-1 Overview of PPT and In the News

16. Practice in Hypothesis Generation
SES
Show the class all the numbers on the table.
Teacher Note: Divide the class into groups to study these distributions and generate hypotheses as to the causes of these deaths.
DrugEpi 2-1 Overview of PPT and In the News

17. Descriptive Epidemiology
SES
The correct hypothesis that explains this distribution is the sinking of the Titanic in 1912.
Discuss with students how the descriptive epidemiology of this tragedy came about.
Looking more deeply into hypothesis as to how these deaths are distributed by gender, age, and social status, what hypothesis could explain the low death rate for children, except for those of the lower class? (children of higher SES were put on lifeboats)
What hypothesis might explain why is the death rate for upper class women lower than that of lower class women? (Higher SES people had more access to the lifeboats)
Who might be the unknown people on the listing. (The crew)
Ask students to list the types of conclusions they could draw in broader terms, like lower class children are more impacted than other children by the “event or disease.” These conclusions could apply to a variety of health states or diseases
Teacher note:. Be sure students understand that the Titanic example is just an exercise to guess an event that is after the fact. In the real world of descriptive epidemiology, we usually do not know what has happened and collect information on PPT that will suggest hypotheses.
DrugEpi 2-1 Overview of PPT and In the News

18. Descriptive Epidemiology
Ask students to figure out in what year Edith Haisman died. (If she was 15 in 1912 and she died at 100, 85 years later, = 1997.)
Here are a few websites that have Titanic passenger information.
DrugEpi 2-1 Overview of PPT and In the News

19. Descriptive Epidemiology
Ask students to identify the event in the picture (Superdome area after Hurricane Katrina, 2005).
Explore with students how the people involved here had a descriptive epidemiology - person, place, and time characteristics that are different from people who were not in this situation. Hypotheses may include:
People with lower incomes who did not have transportation out of New Orleans (person)
People who lived in vulnerable locations in New Orleans (place)
People who happened to live in New Orleans in August of 2005 (time).
As with the Titanic, the descriptive epidemiology of an event (health-related or otherwise) provides clues as to why some people were affected and others were not.
Extending the parallel to the Titanic, ask students to identify on the picture the “lifeboats.” (busses on left) Ask students to identify characteristics of people who were not in this situation (people who owned cars, people from New Orleans who did not believe they would be in danger from the hurricane)
Teacher Note: This example is intended to show students that there are modern-day examples of descriptive epidemiology of dramatic health-related events. As with the Titanic example, the New Orleans example is just an exercise to describe the event whose cause is known. In the real world of descriptive epidemiology, we usually do not know what has happened and collect information on PPT that will suggest hypotheses.
DrugEpi 2-1 Overview of PPT and In the News

20. A Mysterious Ailment A Mysterious Ailment
By Jerry Bishop, Staff Reporter of the Wall Street Journal
A mysterious, often fatal illness is breaking out in epidemic proportions among young homosexual men and drug users. More than 180 cases of the strange illness have been reported since last summer to the federal Center for Disease Control in Atlanta. As of last Friday, at least 74 of the victims have died. All the victims are men and 90% of them are either homosexual or bisexual. Many of the victims are drug users. The illness is characterized by months of fever, malaise, and drastic weight loss. In almost all cases the patients develop overwhelming infections of one or more of a dozen different viruses, bacteria or protozoa. The infecting microbes are types that do not ordinarily cause overt human disease. Many of the patients also develop a rare type of cancer. To the astonishment of medical scientists, most of the patients appear to have recently developed a defect in their immune systems that prevents them from fighting off infections. The infections are extremely difficult to control with antibiotics and antiviral drugs. "We are reasonably confident that this is, in fact, a new medical problem," said Dr. Harold Jaffe, an epidemiologist on a new task force organized by the Center for Disease Control to search for the cause of the illness. In an effort comparable to that launched last year to unravel the mystery of toxic shock syndrome, the center's task force is trying to find out whether a new germ has emerged or whether something in the environment has changed to account for the sudden outbreak of the illness. For example, the task force is checking into the use of sexual stimulants by the victims on the possibility these chemicals can impair the immune system and leave the user vulnerable to infections. Among such stimulants are chemicals that are inhaled. These include amyl nitrate sold in glass vials, known by the street name "poppers" and isobutyl nitrate sold as "liquid incense." First hints that some unusual illness was breaking out came earlier this year when researchers in New York and Los Angeles reported cases of both a rare kind of pneumonia and a rare cancer called Kaposi's sarcoma occurring in a few young men. The men were either homosexual or drug users or both. The disease center alerted doctors and health officials around the country last summer to the strange ailment. This week's New England Journal of Medicine, published today, devotes three articles to describing 19 of the patients, six of whom died. Publishing three lengthy articles on the same illness is unusual for the medical
Tell students that they will now examine the early descriptive epidemiology of an actual disease whose cause was completely unknown in the beginning. They will see this disease described in terms of person, place, and time, identify early disease-causing hypotheses, and support and refute these early hypotheses based on the descriptive epidemiologic evidence.
Ask students to read the article “The Mysterious Ailment.”
Teacher Note: Do not tell students that the disease is AIDS. In 1981, when the article they read for this investigation was written, the disease was not referred to as AIDS. Let students realize this as the investigation progresses. The original article was entitled “Mysterious Ailment Plagues Drug Users, Homosexual Males.”
DrugEpi 2-1 Overview of PPT and In the News

21. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Hypotheses
Draw the “Descriptive Epidemiologic Clues” chart, depicted on the slide, on the board.
DrugEpi 2-1 Overview of PPT and In the News

22. A Mysterious Ailment Give each student a Lesson 2-1 Worksheet.
Ask students to individually fill out their Lesson 2-1 Worksheet based on information in the article
Select students to come to the board and write one descriptive epidemiologic clues for the mysterious ailment in the appropriate column.
When students are finished, their answers should look similar to the next slide.
DrugEpi 2-1 Overview of PPT and In the News

23. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Discuss the identification and sorting of the descriptive epidemiological clues as needed.
Ask students what hypotheses would be supported by the descriptive epidemiology. Write these hypotheses on the board.
Continue until the board looks similar to the next slide.
DrugEpi 2-1 Overview of PPT and In the News

24. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Discuss the hypotheses that were suggested in the article as needed.
… a new germ has emerged ….
… something in the environment ….
… use of sexual stimulants ….
DrugEpi 2-1 Overview of PPT and In the News

25. Hypothesis Generation
Shaking Hands
Whistles
Toilet seats
Poppers
Injection Needles
Ask students to consider several hypotheses that were put forward when the mysterious ailment emerged.
The following slides provide visuals for class discussion of each of these “hypotheses.”
Mosquito Bites
DrugEpi 2-1 Overview of PPT and In the News

26. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Ask students if the hypothesis, “Shaking hands caused the mysterious ailment,” is supported by the descriptive epidemiologic clues mentioned in the article.
Shaking hands caused the mysterious ailment.
DrugEpi 2-1 Overview of PPT and In the News

27. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Ask students if the hypothesis, “Sitting on toilet seats caused the mysterious ailment,” is supported by the descriptive epidemiologic clues mentioned in the article.
Sitting on toilet seats caused the mysterious ailment.
DrugEpi 2-1 Overview of PPT and In the News

28. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Ask students if the hypothesis, “Poppers caused the mysterious ailment,” is supported by the descriptive epidemiologic clues mentioned in the article.
Poppers caused the mysterious ailment.
DrugEpi 2-1 Overview of PPT and In the News

29. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Ask students if the hypothesis, “Using injection needles caused the mysterious ailment,” is supported by the descriptive epidemiologic clues mentioned in the article.
Using injection needles caused the mysterious ailment.
DrugEpi 2-1 Overview of PPT and In the News

30. Descriptive Epidemiologic Clues
A Mysterious Ailment
Descriptive Epidemiologic Clues
Person
Place
Time
Young homosexual men
Large cities
180 cases since last summer
New York
Months of fever, malaise and drastic weight loss
Drug Users
Los Angeles
90% are bisexual or homosexual
Hypotheses
Ask students if the hypothesis, “Mosquito bites caused the mysterious ailment,” is supported by the descriptive epidemiologic clues mentioned in the article?
If students have not identified the mysterious ailment as Acquired Immune Deficiency Disease (AIDS), tell them that the article was written in 1981 and ask them what they think the mysterious ailment was. After discussion, tell students that the mysterious ailment was what today we call AIDS.
Ask students what causes AIDS. (A virus)
Tell students that in 1981 we did not know that.
Mosquito bites caused the mysterious ailment.
DrugEpi 2-1 Overview of PPT and In the News

31. A Mysterious Ailment
Point out to students that the possibility that mosquitoes “… may be involved in AIDS transmission.” was once explored.
DrugEpi 2-1 Overview of PPT and In the News

32. AIDS A Mysterious Ailment Now No One Is Safe From
Point out that, if mosquitoes were “… involved in AIDS transmission,” it is possible that the title of this July 1985 Life magazine cover story would have been true. However, today, in part due to the contributions of the science of epidemiology, we know that someone can eliminate their risk of becoming HIV-infected by not engaging in sexual intercourse or, if they are sexually active, by remaining in a relationship with only one partner who is not infected, and by not using injection drugs.
DrugEpi 2-1 Overview of PPT and In the News

33. A Mysterious Ailment
Tell students about the page on the CDC website that chronicles misconceptions about causes of AIDS.
DrugEpi 2-1 Overview of PPT and In the News

34. Big Ideas in this Lesson (2-1)
Re-Cap
Big Ideas in this Lesson (2-1)
Person, place and time (PPT) describes a disease or other health-related condition in terms of “who, where, and when”
Hypotheses that are suggested by PPT try to explain “why” a disease is distributed as it is
PPT information often leads to more than one reasonable hypothesis
Review Questions:
+ What is descriptive epidemiology? (Describes how a disease is distributed in a population of people.)
+ What are the three main categories of descriptive epidemiologic clues? (Person, place, and time; who, where, and when)
+ What is a hypothesis? (An educated guess.)
+ What is the relationship between descriptive epidemiology and hypotheses? (Descriptive epidemiologic clues provide evidence for formulating hypotheses.)
This project is supported by a Science Education Drug Abuse Partnership Award, Grant Number 1R24DA , from the National Institute on Drug Abuse, National Institutes of Health.
DrugEpi 2-1 Overview of PPT and In the News

35. How is the “disease” (DZ) distributed?
Next Lesson
DZ exercise
How is the “disease” (DZ) distributed?
Why?
In the next lesson (2-2), “In the News,” students will read news articles and identify the descriptive epidemiologic clues of person, place, and time and the hypotheses mentioned in the articles.
DrugEpi 2-1 Overview of PPT and In the News