desain penelitian keperawatan

Copyright © 1999 by W.B.Saunders Company. All rights reserved.

DESAINPENELITIANDESAINPENELITIAN


Riset Quantitative Riset Quantitative

• DescriptiveDescriptive• CorrelationalCorrelational• Quasi-experimentalQuasi-experimental• ExperimentalExperimental

MeningkatMeningkatControlControl


Research DesignResearch Design

• DefinisiDefinisi: Blueprint atau rencana : Blueprint atau rencana detail dalam melaksanakan penelitiandetail dalam melaksanakan penelitian

• Tujuan, Review of Literature, & Tujuan, Review of Literature, & Framework/kerangkaFramework/kerangka

Study DesignStudy Design


Karakteristik DesainKarakteristik Desain

• Memaksimalkan Memaksimalkan controlcontrol meningkatkan validitas hasil.meningkatkan validitas hasil.

• Membantu peneliti merencanakan Membantu peneliti merencanakan dan melaksanakan penelitiandan melaksanakan penelitian

• Tidak spesifik bagian dari langkah Tidak spesifik bagian dari langkah penelitian tetapi berhubungan penelitian tetapi berhubungan dengan seluruh proses penelitiandengan seluruh proses penelitian


Konsep Relevan dg DesainKonsep Relevan dg Desain

• Causality:Causality: AA B B Tekanan Tekanan UlkusUlkus

• Multicausality:Multicausality:MerokokMerokok

Diet tinggi lemakDiet tinggi lemak

Terbatas aktifitasTerbatas aktifitas

PenyakitJantung


Lanjutan….1Lanjutan….1

• ProbabilityProbability:: mengarah keakuratan mengarah keakuratan memprediksi kejadianmemprediksi kejadian

• BiasBias:: Perbedaan temuan dari yang Perbedaan temuan dari yang sebenarnyasebenarnya

• ManipulationManipulation:: Perlakuan atau Perlakuan atau treatmenttreatment


Lanjutan…2Lanjutan…2

• ControlControl• Bisa digunakan dalam desainBisa digunakan dalam desain

• Meningkatkan keakuratan temuan/hasilMeningkatkan keakuratan temuan/hasil

• Kontrol derajatnya meningkat pada Kontrol derajatnya meningkat pada quasi-experimental researchquasi-experimental research

• Kontrol paling tinggi pada experimental Kontrol paling tinggi pada experimental researchresearch


Varying Control in StudiesVarying Control in Studies

Quasi-experimentalQuasi-experimental ExperimentalExperimental

Lower ControlLower Control High ControlHigh Control

Type of Sample Selected:Type of Sample Selected:

Convenience ----------|--------> RandomConvenience ----------|--------> Random





Type of Sample Selected:Type of Sample Selected:

Heterogeneous -----|----> HomogeneousHeterogeneous -----|----> Homogeneous



Measurement Measurement of Dependent Variableof Dependent Variable

CrudeCrude PrecisePrecise

Measurement------|----> MeasurementMeasurement------|----> Measurement



Control Control of Independent Variableof Independent Variable

Limited or Limited or HighlyHighly

no Control ----------|--------> Controlledno Control ----------|--------> Controlled





GroupGroupno comparison group ----> comparison no comparison group ----> comparison group ----> alternative treatment group ----> alternative treatment control group ----> no treatment control group ----> no treatment control groupcontrol group



Selection of GroupsSelection of Groups

No randomization ---------> RandomizationNo randomization ---------> Randomization





Setting SelectedSetting Selected

HighlyHighly

Natural -----------|----------> ControlledNatural -----------|----------> Controlled


Design ValidityDesign Validity

• Measure of truth or accuracy of aMeasure of truth or accuracy of astudy examined with critique &study examined with critique &controlled in conducting a studycontrolled in conducting a study• Statistical conclusion validityStatistical conclusion validity• Internal validityInternal validity• Construct validityConstruct validity• External validityExternal validity


Types of Design ValidityTypes of Design Validity

• Statistical Conclusion Validity Statistical Conclusion Validity -- --

is concerned with whether theis concerned with whether the conclusions about relationships or conclusions about relationships or differences drawn from statistical differences drawn from statistical analyses are an accurate reflection analyses are an accurate reflection of the real world. of the real world.


Statistical Conclusion ValidityStatistical Conclusion Validity

• Low statistical power: Type II error, Low statistical power: Type II error, no significant difference when no significant difference when there is.there is.

• Violated assumptionsViolated assumptions• At least interval dataAt least interval data• Random sampleRandom sample• Normal distributionNormal distribution



• Reliability of Instruments: Reliability of Instruments: consistency in measurementconsistency in measurement• Physiological measures: Precision, Physiological measures: Precision,

such as with temp., BPsuch as with temp., BP• Likert scale: Homogeneity--Reliability Likert scale: Homogeneity--Reliability

with Cronbach’s alpha (.7, .8, .9)with Cronbach’s alpha (.7, .8, .9)• Observations: Stability--Interrater Observations: Stability--Interrater

reliabilityreliability



• Reliability of Treatment Reliability of Treatment • Protocol for treatmentProtocol for treatment• Training of researchersTraining of researchers

• Interrater reliability: # of items Interrater reliability: # of items completed in protocol/ # of items completed in protocol/ # of items on protocol (%)on protocol (%)


• Internal Validity --Internal Validity -- is the extent to which the effectsis the extent to which the effects detected in the study are a detected in the study are a true reflection of reality, true reflection of reality, rather than the result of rather than the result of extraneous variables extraneous variables..

Types of Design Validity


Internal ValidityInternal Validity

• History: event impacting subjects History: event impacting subjects & data collected & data collected

• Maturation of subjects: wiser, tired, Maturation of subjects: wiser, tired, older influencing responsesolder influencing responses

• Testing: learn from being in studyTesting: learn from being in study

• Instruments’ accuracyInstruments’ accuracy


Internal ValidityInternal Validity

• Subject selection nonrandom Subject selection nonrandom & potentially biased& potentially biased

• Mortality: those dropping out Mortality: those dropping out of studyof study

• Diffusion or imitation of treatment: Diffusion or imitation of treatment: control or comparison group control or comparison group has access to treatmenthas access to treatment


• Construct Validity--Construct Validity-- examines the fit between theexamines the fit between the conceptual definitions and conceptual definitions and operational definitions of operational definitions of variables. Link of framework variables. Link of framework concepts & variables studied. concepts & variables studied.



Construct ValidityConstruct Validity

• Validity of instrumentsValidity of instruments• Physiologic measure: AccuracyPhysiologic measure: Accuracy• Scales: construct validityScales: construct validity

• Mono-operation bias: 1 instrumentMono-operation bias: 1 instrumentto measure a variableto measure a variable

• Mono-method bias: 1 type of Mono-method bias: 1 type of instrument, such as attitude scalesinstrument, such as attitude scales


Construct ValidityConstruct Validity

• Subjects guessing outcome of study Subjects guessing outcome of study & acting in a different way& acting in a different way

• Subjects performing for experiment Subjects performing for experiment to be seen in a good light or trying to to be seen in a good light or trying to get an effective treatmentget an effective treatment

• Treatment interactions with more Treatment interactions with more than one treatmentthan one treatment


External Validity---External Validity---is concerned with the extent to is concerned with the extent to which study findings can be which study findings can be generalized beyond the sample generalized beyond the sample used in the study.used in the study.



External ValidityExternal Validity

• Interactions of:Interactions of:• Selection of subjects & treatmentSelection of subjects & treatment• Setting & treatment: closing clinic, Setting & treatment: closing clinic,

nonsupportive staffnonsupportive staff• History & treatment: events History & treatment: events

influence treatmentinfluence treatment


Elements of Strong DesignElements of Strong Design

• Controlling the Environment:Controlling the Environment: selection of the study setting selection of the study setting• Natural settingNatural setting

• Partially controlled setting: clinicPartially controlled setting: clinic• Highly controlled setting: labHighly controlled setting: lab



• Controlling the Equivalence ofControlling the Equivalence of

Subjects & Groups Subjects & Groups

• Random subject Random subject selectionselection

• Random assignment Random assignment to groupsto groups



• Controlling the Treatment (Tx)Controlling the Treatment (Tx)• Tx based on research & practiceTx based on research & practice• Protocol developed for implementationProtocol developed for implementation• Document Tx was implementedDocument Tx was implemented• Checklist to determine extent Tx Checklist to determine extent Tx

was implemented if incompletewas implemented if incomplete• Re-evaluate Tx during studyRe-evaluate Tx during study



• Controlling MeasurementControlling Measurement• ReliabilityReliability• ValidityValidity• # Measurement methods# Measurement methods• Types of instrumentsTypes of instruments



• Controlling Extraneous VariablesControlling Extraneous Variables• Identify & eliminate by sample Identify & eliminate by sample

criteria, setting, designcriteria, setting, design• Random samplingRandom sampling• Sample: heterogeneous, homogeneous, Sample: heterogeneous, homogeneous,

matchingmatching• Statistical controlStatistical control


Problems with Study DesignsProblems with Study Designs

• Inappropriate for purpose Inappropriate for purpose & framework& framework

• Poorly developedPoorly developed

• Poorly implementedPoorly implemented

• Inadequate treatment, sample,Inadequate treatment, sample,measurement methodsmeasurement methods


Critiquing a Study DesignCritiquing a Study Design

1.1. Was the type of design identified? Was the type of design identified?

2.2. Was the study design linked to the Was the study design linked to the purpose &/or objectives, questions, purpose &/or objectives, questions, or hypotheses?or hypotheses?

3.3. Were all variables manipulated Were all variables manipulated or measured?or measured?



4. If the study included a treatment, 4. If the study included a treatment, was it clearly described & was it clearly described & consistently implemented? consistently implemented?

5.5. Were extraneous variables Were extraneous variables identified & controlled?identified & controlled?

6.6. What were the threats to design What were the threats to design validity in this study?validity in this study?



7.7. Was a pilot study performed priorWas a pilot study performed priorto this study? What was the reasonto this study? What was the reasonfor the pilot & the outcome?for the pilot & the outcome?

* Study feasibility* Study feasibility

* Refine design or treatment* Refine design or treatment * Examine validity & reliability * Examine validity & reliability of measurement methods of measurement methods


Identifying a Design in a Quantitative Research Report

Identifying a Design in a Quantitative Research Report


Study PurposeStudy Purpose

• Describe VariablesDescribe Variables• Examine RelationshipsExamine Relationships• Determine DifferencesDetermine Differences• Test a TreatmentTest a Treatment• A Combination of theseA Combination of these


Types of DesignsTypes of DesignsTypes of DesignsTypes of Designs

• Descriptive Study DesignsDescriptive Study Designs• Correlational Study DesignsCorrelational Study Designs• Quasi-Experimental Quasi-Experimental

Study Designs Study Designs• Experimental Study DesignsExperimental Study Designs


Identifying a DesignIdentifying a DesignIdentifying a DesignIdentifying a DesignIs there a treatment?Is there a treatment?

NoNo YesYes

Is the treatment tightly controlledIs the treatment tightly controlledby the researcher?by the researcher?

Is the primary purposeIs the primary purposeexamination of relationships?examination of relationships?

NoNo YesYes

Correlational Correlational DesignDesign

NoNo YesYes

ExperimentalExperimentalStudyStudy

NoNo YesYes

Quasi-ExperimentalQuasi-ExperimentalStudyStudy

Will a randomly assignedWill a randomly assignedcontrol group be usedcontrol group be used

NoNo YesYes

Is the original sample Is the original sample randomly selected?randomly selected?

Will the sample beWill the sample bestudied as a singlestudied as a singlegroup?group?

NoNo YesYes

DescriptiveDescriptiveDesignDesign


Identifying a Descriptive DesignIdentifying a Descriptive DesignIdentifying a Descriptive DesignIdentifying a Descriptive Design

Examining sequences across time?Examining sequences across time?

NoNo

Cross-sectional designCross-sectional design

NoNo YesYes

ComparativeComparativeDescriptiveDescriptiveDesignDesign

One Group?One Group?

DescriptiveDescriptiveDesignDesign

YesYes

Following same subjects across time?Following same subjects across time?

Studying events partitioned Studying events partitioned across time?across time?

CaseCaseStudyStudy

NoNo YesYes

NoNo

Data collectedData collectedacross timeacross time

YesYes

Single unit Single unit of studyof study

NoNo YesYes

Longitudinal Longitudinal StudyStudy

Trend AnalysisTrend Analysis Repeated measures of each subjectRepeated measures of each subject

NoNo YesYes

YesYes NoNo

Cross-sectional designCross-sectional designwith treatment partitioningwith treatment partitioning

Longitudinal design withLongitudinal design withtreatment partitioningtreatment partitioning


Descriptive Study DesignsDescriptive Study Designs

• Typical Descriptive DesignTypical Descriptive Design

• Comparative Descriptive DesignComparative Descriptive Design

• Time Dimensional DesignTime Dimensional Design

• Case Study DesignCase Study Design


Diagramming the DesignDiagramming the Design

• Clarifies the variables to be Clarifies the variables to be measured or manipulatedmeasured or manipulated

• Indicates focus of the study:Indicates focus of the study:description, relationships, description, relationships, differences, &/or testing adifferences, &/or testing atreatmenttreatment


Diagramming the DesignDiagramming the Design

• Identifies data collection process:Identifies data collection process:time for study, treatment time for study, treatment implementation, measurement implementation, measurement of variablesof variables

• Provides direction to Provides direction to data analysisdata analysis


Typical Descriptive DesignTypical Descriptive Design

ClarificationClarification MeasurementMeasurement DescriptionDescription InterpretationInterpretation

PhenomenonPhenomenonof Interestof Interest

Description Description ofof

Variable 1Variable 1











InterpretationInterpretationof Meaningof Meaning

Development ofDevelopment ofHypothesesHypotheses


Comparative Descriptive DesignComparative Descriptive Design

Group IGroup I{variable(s){variable(s)measured}measured}

Group IIGroup II{variable(s){variable(s)measured}measured}

DescribeDescribe

Interpretation Interpretation of Meaningof Meaning

Comparison ofComparison ofGroups on Groups on Selected VariablesSelected Variables

DescribeDescribe DevelopmentDevelopmentof Hypothesesof Hypotheses


Correlational Study DesignsCorrelational Study Designs

• Descriptive Descriptive Correlational Design Correlational Design

• Predictive DesignPredictive Design

• Model-Testing DesignModel-Testing Design


Identifying Type of Correlational DesignIdentifying Type of

Correlational DesignDescribe Describe relationshipsrelationshipsbetween/amongbetween/amongvariables?variables?

PredictPredictrelationshipsrelationshipsbetween/amongbetween/amongvariables?variables?

Test Test theoreticallytheoreticallyproposedproposedrelationships?relationships?

DescriptiveDescriptivecorrelationalcorrelationaldesigndesign

PredictivePredictivecorrelationalcorrelationaldesigndesign

ModelModeltesting testing designdesign


Descriptive Correlational DesignDescriptive Correlational Design

ResearchResearchVariableVariable

11

ResearchResearchVariableVariable

22

DescriptionDescriptionof variableof variable Interpretation Interpretation

of Meaningof Meaning

Examination ofExamination ofRelationshipRelationship

DescriptionDescriptionof variableof variable DevelopmentDevelopment

of Hypothesesof Hypotheses

MeasurementMeasurement


Predictive DesignPredictive Design

ValueValueofof

InterceptIntercept

Value ofValue ofIndependent Independent

VariableVariable11

Value ofValue ofIndependent Independent

VariableVariable22

PredictedPredictedValue ofValue of

Dependent Dependent VariableVariable

++ ++ ==


Study GroupsStudy Groups

• Groups in comparative Groups in comparative descriptive studiesdescriptive studies

• Control groupControl group• Comparison groupComparison group• Equivalent versus Equivalent versus

nonequivalent groupsnonequivalent groups


Pre-Experimental DesignsPre-Experimental Designs

• One-group post-test–only One-group post-test–only designdesign

• Post-test–only design with Post-test–only design with nonequivalent groupsnonequivalent groups

• One-group pretest–post-test One-group pretest–post-test designdesign


Quasi-Experimental DesignsQuasi-Experimental Designs

• Untreated control group design Untreated control group design with pretest & post-testwith pretest & post-test

• Nonequivalent dependent Nonequivalent dependent variables designvariables design

• Removed-treatment design Removed-treatment design with pretest & post-testwith pretest & post-test


Pretest–Post-Test Control Group Design

Pretest–Post-Test Control Group Design

Measurement Measurement of dependent of dependent variablesvariables

Manipulation ofManipulation ofindependentindependentvariablevariable

MeasurementMeasurementof dependentof dependentvariable(s)variable(s)

Randomly selectedRandomly selectedexperimentalexperimentalgroupgroup

PRETESTPRETEST TREATMENTTREATMENT POST-TESTPOST-TEST

Randomly selectedRandomly selectedcontrol groupcontrol group

Treatment:Treatment: Under control of researcherUnder control of researcher

Findings:Findings: comparison of pretest and post-test scorescomparison of pretest and post-test scorescomparison of experimental and control groupscomparison of experimental and control groupscomparison of pretest-post-test differences between samplescomparison of pretest-post-test differences between samples

Example:Example: Your self (1990). The impact of group reminiscence counseling on a depressed elderly Your self (1990). The impact of group reminiscence counseling on a depressed elderly populationpopulation

UncontrolledUncontrolled testingtesting mortalitymortalitythreats to validity:threats to validity: instrumentationinstrumentation restricted generalizability as control restricted generalizability as control

increasesincreases

PRETESTPRETEST POST-TESTPOST-TEST


Post-Test–OnlyControl Group Design

Post-Test–OnlyControl Group Design

Measurement Measurement of independent of independent variablesvariables

MeasurementMeasurementof dependentof dependentvariable(s)variable(s)

Randomly selectedRandomly selectedexperimentalexperimentalgroupgroup

TREATMENTTREATMENT POST-TESTPOST-TEST

Randomly selectedRandomly selectedcontrol groupcontrol group

Treatment:Treatment: Under control of researcherUnder control of researcher

Findings:Findings: comparison of experimental and control groupscomparison of experimental and control groups

Example:Example: Clochesy, Difani & Howe (1991). Electrode site preparation techniques: a Clochesy, Difani & Howe (1991). Electrode site preparation techniques: a follow-up studyfollow-up study

UncontrolledUncontrolled instrumentation instrumentation threats tothreats to mortality mortalityvalidity:validity: limited generalizability as control increaseslimited generalizability as control increases

POST-TESTPOST-TEST


Advantages of Quasi-Experimental DesignsAdvantages of Quasi-Experimental Designs

• More Practical: Ease More Practical: Ease of implementationof implementation

• More Feasible: resources, More Feasible: resources, subjects, time, settingsubjects, time, setting

• More Generalizable: More Generalizable: Comparable to practiceComparable to practice


Advantages of Experimental Designs

Advantages of Experimental Designs

• More Controls: design More Controls: design & conduct of study& conduct of study

• Increased internally valid: Increased internally valid: decreased threats to decreased threats to design validitydesign validity

• Fewer Rival HypothesesFewer Rival Hypotheses


Outcomes ResearchOutcomes Research

• Agencies Supporting Outcomes Agencies Supporting Outcomes ResearchResearch

• Agency for Health Services Agency for Health Services Research (AHSR)Research (AHSR)

• Agency for Health Care Policy Agency for Health Care Policy & Research (AHCPR)& Research (AHCPR)



• Structure of CareStructure of Care• System CharacteristicsSystem Characteristics• Provider CharacteristicsProvider Characteristics• Patient CharacteristicsPatient Characteristics


Outcomes ResearchOutcomes Research• Process of CareProcess of Care

• Ordering testsOrdering tests• Treatments: pharmacological Treatments: pharmacological

& nonpharmacological& nonpharmacological• ReferralReferral• HospitalizationHospitalization• Counseling & educationCounseling & education



• OutcomesOutcomes

• Clinical end pointsClinical end points• Functional statusFunctional status• General well-beingGeneral well-being• Satisfaction with careSatisfaction with care


Critiquing A DesignCritiquing A Design

• Identify elements that were Identify elements that were controlled in the studycontrolled in the study

• Identify possible sources of biasIdentify possible sources of bias• Are there elements that couldAre there elements that could

have been controlled to improve have been controlled to improve the study design?the study design?



• What elements of the design were What elements of the design were manipulated and how were they manipulated and how were they manipulated?manipulated?

• How adequate was the manipulation?How adequate was the manipulation?• What elements should have been What elements should have been

manipulated to improve the validity of manipulated to improve the validity of the findings?the findings?



• Based on your assessment of Based on your assessment of the adequacy of the design, the adequacy of the design, how valid are the findings?how valid are the findings?



• Is there another reasonable Is there another reasonable (valid) explanation (rival (valid) explanation (rival hypothesis) for the study hypothesis) for the study findings other than that findings other than that proposed by the researcher?proposed by the researcher?


QuestionsQuestions

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