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Ch 5: Measurement Concepts Ch 6: Observing Behavior.

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Presentation on theme: "Ch 5: Measurement Concepts Ch 6: Observing Behavior."— Presentation transcript:

1 Ch 5: Measurement Concepts Ch 6: Observing Behavior

2 Reliability  Reliability refers to the consistency or stability of a measure of behavior [p92]  If you weighed yourself now and then at the end of class and you weighed the same both times, you would say the scale is reliable.  True score: The real score on the variable  Measurement error: occurs when a measure yields inconsistent results; the greater the inconsistency, the greater the measurement error

3 Reliability of Measures  How can we assess reliability? Correlation coefficients tell us how strongly two variables are related. - Pearson Product-Moment Correlation Coefficient (noted as r in text) [p93]  C oefficients range from 0.00 to - 1.00 and 0.00 to +1.00  Sign of the coefficient indicates direction  Value of the coefficient indicates the strength

4 Reliability of Measures - 1.00 + 1.00 0.00 Variables covary in opposite directions Variables covary in the same direction

5 Methods of assessing reliability [pp 94-96]  Test-retest reliability: Assesses reliability of a score by measuring the same individuals at 2 points in time  Internal consistency reliability: Assesses reliability of the assessment tool (e.g. test) at one point in time Questions should yield consistent results Split-half reliability – individual’s total score on one half of the test is correlated with the total score on the other half of the test

6 Methods of assessing reliability: Interobserver (Interrater) Reliability  A measure of how often two or more observers agree (are consistent) in their observations. [p96]  Nominal scale: percentage agreement How we assess interobserver reliability: Number of times two observers agree ____________________ X 100 Number of opportunities to agree

7 Construct Validity of Measures [pp 97-100]  Refers to the adequacy of the operational definition of variables  Is the measure that is used actually assessing what it is supposed to assess? If so, it has face validity. Example: Are facial expressions an adequate measure of happiness?

8 Indicators of construct validity Face Validity: The content of the measure appears to reflect the construct being measured. Content Validity: The content of the measure is linked to the universe of content that defines the construct Facial expressions are part of a set of behaviors related to happiness, such as body posture, thoughts, etc.) Example: Are facial expressions an adequate measure of happiness?

9 Indicators of construct validity Predictive Validity: Scores on the measure predict behavior on a criterion measured at a time in the future SAT (Scholastic Aptitude Test predicts future success at a university) Concurrent Validity: Scores on the measure are related to a criterion measured at the same time People who score high on a verbal anxiety test experience increased sweating at the same time People who have happy facial expressions concurrently report feeling happy

10 Indicators of construct validity Convergent Validity: Scores on the measure are related to other measures of the same construct. A score for happy facial expression is related to a score for body posture or mood or optimism Discriminant Validity: Scores on the measure are not related to other measures that are theoretically different. A score for happy facial expression is not related to one for intelligence or cleanliness

11 Measurement Scales Four levels for quantifying behavior: nominal, ordinal, interval, and ratio [p102-105]

12 Nominal scale Classifies behaviors, events, and characteristics into different categories [p102] No numerical or quantitative properties Independent variables are often nominal or a categorical variable

13 Ordinal Scale Measurement scale in which events and behaviors can be rank ordered (i.e, first, second, third, etc.) [p103] Allows categories to be ordered first to last, highest to lowest, biggest to smallest, etc. Quantitative but no values attached to the intervals

14 Interval Scale Measurement scale that allows researcher to specify how far apart two observations are on a given dimension [p104] Difference between the numbers is meaningful Intervals are equal in size Quantitative but no meaningful zero reference point

15 Ratio Scale Measurement scale that is quantitative, with all numerical properties including an absolute zero reference point [p104]

16 Let’s practice! Identify the measurement scale for the following data: Circle your marital status: Married Single Divorced Engaged

17 Let’s practice! Identify the measurement scale for the following data: Circle your marital status: Married Single Divorced Engaged NOMINAL

18 Let’s practice! Identify the measurement scale for the following data: Do you go to work? Yes No

19 Let’s practice! Identify the measurement scale for the following data: Do you go to work? Yes No NOMINAL

20 Let’s practice! Identify the measurement scale for the following data: If you work, how many hours a week do you work? _______

21 Let’s practice! Identify the measurement scale for the following data: If you work, how many hours a week do you work? _______ RATIO

22 Let’s practice! Identify the measurement scale for the following data: Rate your enjoyment of college on the scale below. 12345 Not Very Much Very Much

23 Let’s practice! Identify the measurement scale for the following data: Rate your enjoyment of college on the scale below. 12345 Not Very Much Very Much INTERVAL

24 Let’s practice! Identify the measurement scale for the following data: What is your class standing? Freshman Sophomore Junior Senior

25 Let’s practice! Identify the measurement scale for the following data: What is your class standing? Freshman Sophomore Junior Senior ORDINAL

26 Places to Observe on Campus (Spring 2010) 1. Area in the middle of campus, by the Info Trolley. 2. By the food place on campus which is near the gym/pools. 3. By the statue of the boy overlooking the water feature. 4. Entrance of the SE parking structure (people exiting structure) 5. Entrance of the SE parking structure (people entering structure) 6. Entrance of the SW parking structure (people exiting structure) 7. Entrance of the SW parking structure (people entering structure) 8. By the entrance of the bookstore. 9 In front of C Building, by mirror pools 10. Shuttle stop by U Building 11. Bus stop on Colorado in front of library 12. Passenger drop off/pick up (Colorado B. in front of L Bldg) 13. Starbucks

27 Reactivity Occurs when individuals change their usual behavior, when they know they are being observed [p101] Minimize reactivity by: Allowing time for individuals to become used to the presence of an observer or the recording equipment

28 Time sampling: Researchers choose time intervals for making observations Systematic: Schedule observations to occur at a regular time Random: Use some random means for identifying times for observations Event sampling is used for rare events Situation sampling: Researchers choose different settings, circumstances, and conditions for their observations Sampling Behavior [p116]

29 Classification of Observational Methods Two categories of observational methods: Observation without Intervention Observation with Intervention

30 Observation without Intervention Naturalistic Observation (AKA: field work or field observations ): Observation in natural (“real-world”) settings without an attempt to intervene or change the situation [p110]

31 Participant observation Observer is an active participant in the natural setting he or she observes [p112-113] Norah Vincent “My Life as a Man” Undisguised (unconcealed): people in the setting know they are being observed Disguised (concealed): people don’t know they are being observed

32 Observation without Intervention Physical traces: The remnants, fragments, and products of past behavior Products: Creations, constructions, or other artifacts of earlier behavior

33 Observation without Intervention Physical traces: Evidence that remains from the use or nonuse of an item natural-use traces controlled use traces

34 Natural-use traces Produced without any intervention by the investigator

35 Controlled-use traces Produced with some degree of intervention or manipulation by the investigator

36 Natural use or controlled use trace?

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39 Archival records Public and private documents that describe the activities of individuals, institutions, governments, and other groups [p204]

40 Archival Research [118-121]  A non-reactive measure (or indirect method) for collecting data—when the individual who did the behavior is no longer present  Archival research involves using previously compiled information to answer research questions

41 Running records & records of specific events Running records are continuously kept and updated (e.g., check book) Records of specific events (e.g., diploma)

42 Archival data are used to: test hypotheses as part of a multimethod approach test the external validity of laboratory findings test hypotheses about past behavior assess the effect of a natural treatment

43 Multimethod approach Researchers use a variety of measures to examine a research question

44 Natural treatments Naturally occurring events that impact society and individuals

45 Selective deposit Occurs when some information is selected to be included in the archival record, but other information is not

46 Selective survival Occurs when information is lost or missing from an archival source

47 Content analysis The process of making inferences based on objective coding of archival data [p120]

48 Quantitative analysis Classifying events and behaviors into categories to count their frequency of occurrence [p109] Assign numerical values to responses and measures and then subject the data to quantitative statistical analyses Ex: Count the number of times gender- stereotypical jobs were assigned to characters in the story.

49 Qualitative analysis Subjective judgments about the content in an archival record [p109] Describe behavior or findings based on themes that emerge from the data. Data are nonnumerical and expressed in language and images Ex: Watch the tape of Osama Bin Laden and tell me if you think he is being deceptive.

50 Three Steps of Content Analysis 1) Identify a relevant source 2) Sample selections from the source 3) Code units of analysis

51 Observation with Intervention [p114] Systematic observation: The careful observation of one or more behaviors in a particular setting. Use when: interest is in only a few very specific behaviors observations are quantifiable researcher has developed prior hypothesis

52 Field experiment Researcher manipulates an independent variable in a natural setting and observes behavior (dependent variable) [pp 83, 113]

53 Coding systems for systematic observation… [p115]  are either (1) developed to fit the needs of the particular study or (2) “borrowed” systems developed by others  should be as simple as possible  must allow researchers to easily categorize behaviors

54 Coding systems can involve: Comprehensive records of people’s behavior (e.g., complete records, such as video tapes)—a qualitative record Selecting specific behaviors to record—a quantitative record [pp115-116]

55 Equipment & Narrative Records Used when researchers want a complete (comprehensive) reproduction of people’s behavior [pp 115-116] Examples: video and audio recordings, field notes

56 Systematic Observation: Methodological Issues [pp115-116] 1.Equipment: can fail 2.Reactivity: the probability that the presence of the observer will affect behavior 3.Reliability: refers to how stable/consistent the measure is over time or between observers 4.Sampling: refers to how participants and behaviors are chosen to be studied 1.Larger samples of participants and multiple samples of behavior can increase both internal and external validity.

57 Case Studies [pp117-118]  A case study provides a description of an individual. Usually the individual is a person, but may also be a setting. A psychobiography is a type of case study in which a researcher applies psychological theory to explain the life of an individual.

58 Case Studies…  are done when an individual possesses a particularly rare, unusual, or noteworthy condition.  provide unique data about some psychological phenomenon  and the insights gained from them may lead to other research using other methods


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