Correlational Research

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Correlational Research

• The Survey Asking People About Themselves

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Outline

• Heatherton Study
• Types of Surveys
• Methods of Administration
• Questionnaires Inventories
• Demographic questionnaires
• Measuring Attitudes Behavior
• Self-report instruments
• Accuracy reliability validity
• Reactivity in survey research
• Social desirability

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Heatherton et al.s (1997) Study of Eating
Attitudes and Behaviors

• Research Question Do young men and womens
  attitudes and behaviors around eating change over
  time?
• Design a longitudinal survey
• Method In 1982, 800 female and 400 male college
  students were selected and completed surveys.
• In 1992 participants were re-contacted and asked
  to complete a second survey.

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Heathertons Measures

• A demographic questionnaire
• Described age, marital status, ethnicity,
  education, SES.
• Included questions about height, weight, and
  eating behaviors.
• A measure of eating attitudes the EDI (Eating
  Disorder Inventory).
• Five subscales were used
• Drive for Thinness
• Bulimia
• Maturity fears
• Perfectionism
• Interpersonal distrust

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Elements of a Survey

• Methods of Administering a Survey
• Survey Designs
• Survey Instruments
• Accuracy Issues

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Methods of Administration

• In Person
• Interviewer records answers
• Participant fills out measures
• By Mail
• Telephone Survey
• Internet Survey

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Types of Survey Designs

• Cross-sectional Surveys
• A sample of individuals is surveyed once. Gives
  information about participants at one point in
  time.
• Longitudinal Surveys
• A sample of individuals is surveyed more than
  once over weeks, months, or years.
• Reveals change over time
• Heatherton (1997) Eating Disorders Study

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Types of Survey Designs (cont.)

• Successive Independent Samples Design
• Different samples are drawn from a population
  over a period of time.
• This design reveals changes in a population over
  time Public opinion polls presidential ratings

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Self-Report Measures

• Tell us about yourself!

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Questionnaires

• Survey research collects data on a sample of
  participants by using self-report questionnaires.
• These questionnaires are designed or selected by
  the researcher to measure the variables of
  interest (eating attitudes behaviors).
• Questionnaires are designed to be both accurate
  and user-friendly.

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Describing the Participants Demographic Variables

• The set of individuals who participated in the
  survey (the sample) must be described. Why?
• Demographic variables are measured. These
  include
• Age
• Gender
• Ethnicity
• Education
• Marital Status
• Socioeconomic Status (SES)

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Measuring Attitudes Behavior

• Questionnaires are used to measure the variables
  of interest, which may include
• Attitudes
• Behaviors
• Emotions
• Moods
• Symptoms
• These are called self-report measures, also
  known as inventories, scales, or
  instruments.

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Create anew or use the tried-and-true?

• The instruments used in survey research can come
  from two sources
• Those constructed by the researcher.
• Tailored for the study
• Need to be validated
• Those constructed by other psychologists and
  published in journals.
• Standardized
• Used in many studies

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Self-Report Likert Scale Questions

• Instructions Please circle the appropriate
  number to indicate the extent to which you agree
  or disagree using the following scale
• 1 Strongly disagree
• 2 Disagree
• 3 Neutral
• 4 Agree
• 5 Strongly agree

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Examples of Questionnaire Items Assessing
Self-attitudes (Likert Scale)(1 strongly
disagree, 5 strongly agree)

• On the whole, I am satisfied with myself.
• I find it difficult to be alone.
• People will think less of me if I make a mistake.
• I always look on the bright side of things.
• People consider me to be a pessimist.

• 1 2 3 4 5
• 1 2 3 4 5
• 1 2 3 4 5
• 1 2 3 4 5
• 2 3 4 5

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Reactivity in Survey Research

• A significant accuracy problem in survey research
  can arise in the form of subject bias.
• Subject bias tendency for a participant to
  respond to questions in a certain way throughout
  the test.
• Subject bias creates a systematic distortion in
  the accuracy (truthfulness) of responses.
• Example Social Desirability Bias the effort to
  look good to others.

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Drive For Thinness Subscale (EDI)

• I think about dieting.
• I feel extremely guilty after overeating.
• I am terrified of gaining weight.
• I exaggerate or magnify the importance of weight.
• I am preoccupied with the desire to be thinner.
• If I gain a pound, I worry that I will keep
  gaining.
• I eat sweets and carbs without feeling nervous.
  (reverse scored)

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Establishing a Measures Accuracy

• A measure must be shown to be both RELIABLE and
  VALID before it can be used with confidence.
• There are procedures psychologists use to
  establish reliability and validity.
• In a study, data on these are presented in the
  measures section.

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Reliability Validity

• Reliability
• Does the instrument perform consistently over
  time?
• Low reliability your bathroom scale shows a
  difference of 2 lbs each time you step on it.

• Validity
• Does the instrument measure what it intends to
  measure?
• Low validity shoe size as a measure of athletic
  ability.

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Measuring or establishing the reliability of a
measure
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Achieving Test-Retest Reliability

• Test-retest reliability is expressed as a
  correlation coefficient (between T1 and T2).
• The time interval between the test the retest
  will affect reliability (participants change).
• Variation in participants mood environmental
  factors will affect reliability.
• The trait being measured will also affect
  reliability! E.g. personality traits are
  relatively stable, mood is not.

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Ways to Increase a Measures Reliability

• Increase the number of items used to measure a
  construct.
• Administer the test to a diverse sample of
  individuals.
• Make sure the testing situation is free of
  distractions, and that instructions are clear.

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Establishing that a Measure is Valid

• Testing Construct Validity
• Correlate a groups performance on the new test
  with performance on an established measure of the
  same construct.
• E.g. Does Kogans Depression Scale correlate well
  with the Beck Depression Inventory?
• Do both tests seem to measure the same construct?