Causal Comparative Research At least two different groups are compared on a dependent variable or measure of performance (called the “effect”) because the independent variable (called the “cause”) has already occurred or cannot be manipulated. Dependent variable-the change or difference occurring as a result of the independent variable. Independent variable- an activity of characteristic believed to make a difference with respect to some behavior.

1. Causal-ComparativeCausal-Comparative
ResearchResearch
July 23, 2001July 23, 2001
EAF 410EAF 410

2. What is it?What is it?
• AssociationalAssociational
• Differences between/among groupsDifferences between/among groups
– Categorical dataCategorical data
– Differences already existDifferences already exist
• Ex post factoEx post facto
• Much research in medicine &Much research in medicine &
sociologysociology

3. ExamplesExamples
• What are the effectsWhat are the effects
of teacher gender onof teacher gender on
student behaviorstudent behavior
• How areHow are
administrativeadministrative
decisions affecteddecisions affected
by genderby gender
• What causesWhat causes
students to join thestudents to join the
glee club?glee club?
• How are teachingHow are teaching
styles affected bystyles affected by
graduate studies?graduate studies?

4. Type 1Type 1
• Exploration ofExploration of effectseffects caused bycaused by
membership in a groupmembership in a group
– What differences in student behaviorWhat differences in student behavior
are caused by gender?are caused by gender?

5. Type 2Type 2
• StudiesStudies causescauses of groupof group
membershipmembership
– Why do ISU students enroll in EAFWhy do ISU students enroll in EAF
410 during the summer session?410 during the summer session?

6. Type 3Type 3
• Studies theStudies the consequencesconsequences of anof an
interventionintervention
– How do students who have takenHow do students who have taken
EAF 410 evaluate research articles?EAF 410 evaluate research articles?

7. Causal Link TentativeCausal Link Tentative
• DoesDoes gendergender cause differences?cause differences?
– Girls read betterGirls read better
– Boys are disciplined moreBoys are disciplined more
• Other probable links in the causalOther probable links in the causal
chainchain

8. Basic ApproachBasic Approach
• Noted difference between twoNoted difference between two
groupsgroups
• Look for causes/consequencesLook for causes/consequences

9. Similarities withSimilarities with
Correlational ResearchCorrelational Research
• AssociationalAssociational
• Attempt to explain phenomenaAttempt to explain phenomena
• Often lead to experimental researchOften lead to experimental research
• Don’t allow variable manipulationDon’t allow variable manipulation
• Attempt to explore causationAttempt to explore causation

10. Causal-ComparativeCausal-Comparative
-compare groups-compare groups
-categorical variable(s)-categorical variable(s)
-crossbreak tables-crossbreak tables
CorrelationalCorrelational
-individual scores-individual scores
-quantitative variables-quantitative variables
-scatterplots &-scatterplots & rr
Similarities withSimilarities with
Correlational ResearchCorrelational Research

11. Steps InvolvedSteps Involved
• Identify & clarify research problemIdentify & clarify research problem
– Several alternative hypothesesSeveral alternative hypotheses
• Select subjects (groups)Select subjects (groups)
– Homogenous on some variablesHomogenous on some variables
• InstrumentationInstrumentation
– No limitsNo limits

12. Steps InvolvedSteps Involved
(continued)(continued)
• DesignDesign
– Groups differ on specific variableGroups differ on specific variable
– Groups compared on other variable(s)Groups compared on other variable(s)

13. Evaluating ThreatsEvaluating Threats
• What other factors affect theWhat other factors affect the
comparison variable?comparison variable?
• What is the likelihood of theWhat is the likelihood of the
groups differing on these factors?groups differing on these factors?
• Evaluate threats on likelihood ofEvaluate threats on likelihood of
their effect and plan to control.their effect and plan to control.

14. Survey ResearchSurvey Research
July 23, 2001July 23, 2001
EAF 410EAF 410

15. Three CharacteristicsThree Characteristics
• Information collected to describeInformation collected to describe
• Information collected by askingInformation collected by asking
questionsquestions
• Information collected from aInformation collected from a
samplesample

16. Major PurposeMajor Purpose
• To describe the characteristics of aTo describe the characteristics of a
populationpopulation
• Not so concerned aboutNot so concerned about whywhy
• Concerned aboutConcerned about what iswhat is

17. Types of SurveysTypes of Surveys
• Cross-sectional StudyCross-sectional Study
– information collected at just oneinformation collected at just one
point in timepoint in time
• Longitudinal StudyLongitudinal Study
– information collected at differentinformation collected at different
points in timepoints in time

18. Types of LongitudinalTypes of Longitudinal
StudiesStudies
• TrendTrend
– Different samplesDifferent samples
– Population may changePopulation may change
• CohortCohort
– Different samplesDifferent samples
– Population doesn’t changePopulation doesn’t change

19. Types of LongitudinalTypes of Longitudinal
StudiesStudies (continued)(continued)
• PanelPanel
– Same sampleSame sample
– Population doesn’t changePopulation doesn’t change

20. Steps in Survey ResearchSteps in Survey Research
• Clearly define objectivesClearly define objectives
• Construct clear questionsConstruct clear questions
• Sample (unit of analysis)Sample (unit of analysis)
• Collect dataCollect data
– ““live” to a grouplive” to a group
– mailmail
– phonephone
– face-to-face interviewsface-to-face interviews

21. Preparing the InstrumentPreparing the Instrument
• Not too longNot too long
• Questions easy to answerQuestions easy to answer
• Carefully wordedCarefully worded
– can be asked as writtencan be asked as written
– will mean same to allwill mean same to all
– can be answeredcan be answered
– will be answeredwill be answered

22. Types of QuestionsTypes of Questions
• Closed-endedClosed-ended
– answers providedanswers provided
• Open-endedOpen-ended
– respondent provides answersrespondent provides answers

23. Suggestions for Closed-Suggestions for Closed-
Ended QuestionsEnded Questions
• UnambiguousUnambiguous
• Simple focusSimple focus
• ShortShort
• Common languageCommon language
• ““Unbiased” termsUnbiased” terms
• Not leading questionsNot leading questions
• No double negativesNo double negatives

24. Suggestions for QuestionsSuggestions for Questions
• Try them out on a similar sampleTry them out on a similar sample
• Make them look goodMake them look good
• Have follow-up questionsHave follow-up questions
– contingency questions -- contingentcontingency questions -- contingent
on answer to previous questionon answer to previous question

25. NonresponseNonresponse
• Some will not return surveySome will not return survey
• Some items will not be answeredSome items will not be answered
• Can use random replacementCan use random replacement