quantitative research. descriptive research also called “survey research” also called “survey...

Quantitative ResearchQuantitative Research

Descriptive ResearchDescriptive Research

• Also called “Survey Research”Also called “Survey Research”

• Describes the way things existDescribes the way things exist

• Data collected Data collected – Test hypothesisTest hypothesis– Or to classify opinions on issues/topicsOr to classify opinions on issues/topics


• Most common research Most common research – Surveys conductedSurveys conducted– Many fields covered: education, politics, Many fields covered: education, politics,

social and economicsocial and economic

• More complicated than one may More complicated than one may thinkthink


• Classified by data collection methodClassified by data collection method– Self report (survey)Self report (survey)– Observation (participants watched)Observation (participants watched)


• Survey typesSurvey types– Cross-sectionalCross-sectional

•Data collected at one point in timeData collected at one point in time

– LongitudinalLongitudinal•More than once to measure growth or More than once to measure growth or

changechange


• Cross-sectional surveyCross-sectional survey– Single point in time may not provide Single point in time may not provide

perspective needed perspective needed – Example: census surveyExample: census survey


• Longitudinal surveyLongitudinal survey– Collected multiple times from different Collected multiple times from different

samples and groupssamples and groups– Four types of longitudinal surveysFour types of longitudinal surveys

•Trend, cohort, panel, and follow-upTrend, cohort, panel, and follow-up


• Trend surveyTrend survey– How are attitudes changing or How are attitudes changing or

consistent among changing sample consistent among changing sample groupsgroups

• Cohort surveyCohort survey– Different samples from the same group Different samples from the same group

are surveyed over several time periodsare surveyed over several time periods


• Panel surveyPanel survey– Same group and sample are surveyed Same group and sample are surveyed

over timeover time

• Follow-up surveyFollow-up survey– Similar to panel study, but performed Similar to panel study, but performed

after the panel study complete after the panel study complete (examines later changes)(examines later changes)

– Usually to evaluate a college Usually to evaluate a college instructional programinstructional program


• Conducting self-report researchConducting self-report research– Standardized, quantifiable information Standardized, quantifiable information

collectedcollected– Questionnaire is writtenQuestionnaire is written– Interview is an in-person Q&A session Interview is an in-person Q&A session

between researcher and participantbetween researcher and participant


• Conducting a Questionnaire studyConducting a Questionnaire study– Most efficientMost efficient– Larger data sample collectedLarger data sample collected– Mailing is preferredMailing is preferred


• Topic under investigation must be Topic under investigation must be significant for subjects to respondsignificant for subjects to respond

• Problem defined in specific objectivesProblem defined in specific objectives– Each item on survey must directly relate Each item on survey must directly relate

to objectivesto objectives


• ParticipantsParticipants– Chosen from appropriate sampleChosen from appropriate sample– Possess needed information and are Possess needed information and are

willing to share itwilling to share it


• QuestionnaireQuestionnaire– Brief, easily answeredBrief, easily answered– Structured (close-ended) response Structured (close-ended) response

choiceschoices•Facilitate easy responsesFacilitate easy responses

•Data analysis objective and efficientData analysis objective and efficient


• QuestionnaireQuestionnaire– Structured items are scaled (ex. Likert)Structured items are scaled (ex. Likert)– Unstructured items – complete freedom Unstructured items – complete freedom

of responseof response•Provide more depthProvide more depth

•Difficult to measureDifficult to measure


• QuestionnaireQuestionnaire– Item constructionItem construction

•Each questions focuses on one conceptEach questions focuses on one concept

•Concisely wordedConcisely worded

•Concepts or terms with multiple Concepts or terms with multiple connotations are definedconnotations are defined

•Avoid leading questionsAvoid leading questions


• QuestionnaireQuestionnaire– PretestingPretesting

•Smaller, but similar groupSmaller, but similar group

•Data will indicate any measurement Data will indicate any measurement difficulties and suggest improvementdifficulties and suggest improvement

•Make sure it measures what it is designed to Make sure it measures what it is designed to measuremeasure


• QuestionnaireQuestionnaire– Analyzing resultsAnalyzing results

• Indicate % of respondents who selected Indicate % of respondents who selected each alternative answer for each itemeach alternative answer for each item

•When possible, also analyze summed item When possible, also analyze summed item clustersclusters

– Groups of items focusing on same issueGroups of items focusing on same issue– Variable relationships can be investigated (female Variable relationships can be investigated (female

vs. male responses) for each clustervs. male responses) for each cluster


• Interview StudyInterview Study– More in-depth data collected if More in-depth data collected if

successfulsuccessful– More expensive and time-consumingMore expensive and time-consuming– Smaller sample population usedSmaller sample population used


• Interview StudyInterview Study– Written guide for administrator Written guide for administrator – Includes any prompts or additionally Includes any prompts or additionally

allowed probingallowed probing– Standardized, comparable data requires Standardized, comparable data requires

all interviews must be conducted in all interviews must be conducted in same mannersame manner


• Interview StudyInterview Study– Uses same guidelines from Uses same guidelines from

questionnaire constructquestionnaire construct– Responses recorded manually or by Responses recorded manually or by

recording device (participants must recording device (participants must consent)consent)

Correlational ResearchCorrelational Research

• Data collected to determine:Data collected to determine:– Is there a relationship between two Is there a relationship between two

variables?variables?– To what degree is the relationship?To what degree is the relationship?

• Degree of relationship is expressed Degree of relationship is expressed as a correlation coefficientas a correlation coefficient


• Correlation coefficientCorrelation coefficient– Measured on a scale from +1.00 to -1.00Measured on a scale from +1.00 to -1.00

• If variables highly related, correlation If variables highly related, correlation coefficient near +1.00 or -1.00 will be coefficient near +1.00 or -1.00 will be obtainedobtained

• If not related, a correlation coefficient If not related, a correlation coefficient near .00 will be obtainednear .00 will be obtained


• Correlation coefficientCorrelation coefficient– InterpretationInterpretation

•Lower than (+ or - ) .35 – low or noneLower than (+ or - ) .35 – low or none

•Between (+ or -) .35 and .65 – moderateBetween (+ or -) .35 and .65 – moderate

•Higher than (+ or -) .65 – High relationshipHigher than (+ or -) .65 – High relationship


• Correlation coefficientCorrelation coefficient– InterpretationInterpretation

•A high relationship between two variables A high relationship between two variables doesn’t necessarily mean one causes the doesn’t necessarily mean one causes the otherother

•There may be a third variable that causes There may be a third variable that causes them boththem both

Causal-Comparative Causal-Comparative Research Research • Determines cause for differences in Determines cause for differences in

behavior or status of groups of behavior or status of groups of individualsindividuals

• The effect and the cause have already The effect and the cause have already happenedhappened

• Mostly studied in retrospectMostly studied in retrospect

• Example: Pre-school and social Example: Pre-school and social adjustment in 1adjustment in 1stst grade grade

Causal-Comparative Causal-Comparative ResearchResearch

• Prospective approach slightly Prospective approach slightly differentdifferent– Start with a cause and investigate its Start with a cause and investigate its

effect on a variableeffect on a variable– Example: social promotion in 7Example: social promotion in 7thth grade grade


• The independent variableThe independent variable– A behavior or characteristic believed to A behavior or characteristic believed to

influence some other behavior or influence some other behavior or characteristic (pre-school attendance)characteristic (pre-school attendance)

• The dependent variableThe dependent variable– The change or difference in a behavior The change or difference in a behavior

or characteristic due to an independent or characteristic due to an independent variable (social adjustment in 1variable (social adjustment in 1stst grade) grade)


• The independent variableThe independent variable– Not manipulated in Causal-Comparative Not manipulated in Causal-Comparative

ResearchResearch– This is the major difference between this This is the major difference between this

and Experimental Researchand Experimental Research– In Causal-Comparative Research, groups In Causal-Comparative Research, groups

are already formed and divided by the are already formed and divided by the independent variableindependent variable


• The independent variableThe independent variable– Basic Causal-Comparative Research Basic Causal-Comparative Research

design finds two groups differing on design finds two groups differing on some independent variable, and some independent variable, and comparing them on a dependent comparing them on a dependent variablevariable


• Groups may differ in characteristicsGroups may differ in characteristics

• Select samples that represent their Select samples that represent their respective populationsrespective populations


• Data analysis and interpretationData analysis and interpretation– Descriptive statisticsDescriptive statistics

•The mean – average performance of group The mean – average performance of group on a measure of some variableon a measure of some variable

•Standard deviation – measure the “spread” Standard deviation – measure the “spread” of scores around the mean (are they of scores around the mean (are they relatively close together or widely spread)relatively close together or widely spread)


• Data analysis and interpretationData analysis and interpretation– Inferential statisticsInferential statistics

•t test – indicates if there is a significant t test – indicates if there is a significant difference between the means of two groupsdifference between the means of two groups

•Analysis of variance – significant differences Analysis of variance – significant differences between means of three or more groupsbetween means of three or more groups

•Chi square – does an event occur more Chi square – does an event occur more frequently in one group than another?frequently in one group than another?


• Data analysis and interpretationData analysis and interpretation– Use cautionUse caution– Alleged cause-effect relationship may be Alleged cause-effect relationship may be

the effect or a third factor may cause the effect or a third factor may cause the independent and dependent the independent and dependent variablesvariables

– Correct order of causality – which Correct order of causality – which variable caused which? The one that variable caused which? The one that occurred firstoccurred first

Experimental ResearchExperimental Research

• Researcher manipulates at least one Researcher manipulates at least one independent variableindependent variable

• Controls other variablesControls other variables

• Observes effect on one more Observes effect on one more dependent variablesdependent variables


• Independent variableIndependent variable– a.k.a. experimental variable, cause, or a.k.a. experimental variable, cause, or

treatmenttreatment– Believed to make a difference in some Believed to make a difference in some

performanceperformance


• Dependent variableDependent variable– a.k.a. criterion variable, effect, or a.k.a. criterion variable, effect, or

posttestposttest– Outcome of the studyOutcome of the study– Measure of change or difference Measure of change or difference

resulting from independent variable resulting from independent variable manipulationmanipulation


• Experimental studies yield the Experimental studies yield the soundest evidence when conducted soundest evidence when conducted wellwell

• Prove or disprove hypothetical cause Prove or disprove hypothetical cause and effect relationshipsand effect relationships


• The processThe process– Select/define problemSelect/define problem– Guided by one hypothesisGuided by one hypothesis– Researcher in controlResearcher in control– Experimental group receives unique Experimental group receives unique

treatmenttreatment– Control group receives different Control group receives different

treatmenttreatment


• The processThe process– All other variables are equal to both All other variables are equal to both

groups that may effect dependent groups that may effect dependent variablevariable

– After exposed to treatment for some After exposed to treatment for some time, researcher applies dependent time, researcher applies dependent variable and measures differencesvariable and measures differences


• Manipulation and controlManipulation and control– Sets experimental apart from all othersSets experimental apart from all others

• Three forms of independent variable Three forms of independent variable manipulationmanipulation– Presence versus absence (A vs. no A)Presence versus absence (A vs. no A)– Presence varying degrees (much A vs. little Presence varying degrees (much A vs. little

A)A)– Presence of one kind/another kind (A vs. B)Presence of one kind/another kind (A vs. B)


• Manipulation and controlManipulation and control– Control: efforts to remove outside Control: efforts to remove outside

influences of any variable (other than influences of any variable (other than independent variable) that may affect independent variable) that may affect dependent variabledependent variable


• Two controlled variablesTwo controlled variables– Participant variablesParticipant variables

•Members of different groups may have Members of different groups may have characteristic differencescharacteristic differences

– Environmental variablesEnvironmental variables•Any change in experimental setting that Any change in experimental setting that

may influence performance differencesmay influence performance differences

Single-Subject Experimental Single-Subject Experimental ResearchResearch

• Studies individual behavior changeStudies individual behavior change

• Result of some treatment formResult of some treatment form

• Repeated formulaRepeated formula– Receives no treatment or interventionReceives no treatment or intervention– TestedTested– Receives treatment / interventionReceives treatment / intervention– TestedTested

quantitative research. descriptive research also called “survey research” also called “survey...

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survey research

descriptive research

quantitative research

census survey slide

followup slide

efficient slide

selfreport research

common research surveys