study designs in hand therapy research - punita v. solanki
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Presented at the 3rd Annual National Conference of Society for Hand Therapy, India on 13th September 2014 at Thane, Mumbai, IndiaTRANSCRIPT
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Punita V. SolankiMSc (O.T.), YFT-ISSA, Level I PIA Trainer, ADCR-ACEConsultant Occupational Therapist, Mumbai
Mobile: +91-9820621352Email id: [email protected]
Study Designs in HandTherapy Research
3rd Annual National Conference of Society forHand Therapy, India,
13th September 2014, SaturdayThane, Mumbai
Table of Contents
1. Research Pathway to Study Design
2. Study Design Selection based on Research Question.
3. Common Terms Used in Research Studies.
4. Types of Study Designs with Examples.
5. Types of Controls Used in Experimental Studies.
6. Types of Randomization & Blinding.
7. Level of Evidence & Grades of Recommendations.
8. Quiz
Disclaimer
The presentation is entirely the effort of thepresenter, based on the past and present experiencesin clinical research; academic training and fromthorough literature search on the related topic.The company, organization and the hospitals wherethe presenter is associated, has no bearing with thepresentation. It is entirely the view of the presenterbased on the existing evidence.
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Research Pathway to Selection of Study Design
Study Design
Hypothesis
Specific Research Question
Research Problem
Review of Literature
Novel Idea
Punita V. SolankiOccupational
Therapist13th September 20143rd Annual NationalConference of SHT,
India
Study Design Selection
The clinical question determines whichstudy designs are appropriate. So firstselect the research objective and aim of thestudy and then choose the study design.
One clinical question can be answeredby more than one study design.
No single study design can answer allthe clinical questions.
No single study design fits all the needs& circumstances of the research.
Punita V. SolankiOccupational
Therapist
Study Design Selection
The Clinical Research QuestionThe Study Aims & ObjectivesSample Population & Sample Size AvailabilityTime & Cost ConcernsEthical ConcernsHow, When & Where the Study findings are to be
Used.Concerns about the Robustness of the Study for
its efficacy (internal validity) and its effectiveness(external validity) for application of findings ingeneral population.
Factors affecting the selection of study designcould be many and they are:
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India
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Classification of Medical Research
*1, sometimes known as experimental research; *2, analogous term: interventional; *3, analogous term: noninterventional or nonexperimental
Punita V. SolankiOccupational
Therapist
Research Method Approaches
13th September 20143rd Annual NationalConference of SHT,
India
QualitativeResearch MethodApproach
QuantitativeResearch MethodApproach
Mixed MethodsResearchApproach
Ethnography ObservationalDescriptive Research
SequentialProcedures
Grounded Theory ObservationalAnalytical Research
ConcurrentProcedures
Case Study Experimental/Interventional Research
TransformativeProcedures
PhenomenologicalResearch
Narrative Research
Source: Research Design: Qualitative, Quantitative and Mixed Methods Approaches. JohnW. Creswell. Second Edition. 2003. Sage Publications . In Chapter 1: A Framework forDesign.
Punita V. SolankiOccupational
Therapist
Qualitative Versus Quantitative Study Designs
13th September 20143rd Annual NationalConference of SHT,
India Understands theoryFavors FieldworkInterview/ObservationDiscovering frameworksTextual (words)Theory (Hypothesis)
generatingQuality of informant is
more importantSubjectiveEmbedded knowledgeMultiple sources of
evidence (triangulation)Models of analysis: text
or words of intervieweesOpen (Inductive) Vs Pre-
Structured (Deductive)
Predicts theoryFavors Laboratory workTest/Scale/Score/SurveyExisting frameworksNumericalTheory (Hypothesis)
testing (experimental)Sample size core issue in
reliability of dataObjectiveFrom PublicSingle-criterion outcome
(albeit multidimensional)Model of analysis:
parametric, non-parametricObservational Vs
Experimental/Interventional
Qualitative: Quantitative:
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Punita V. SolankiOccupational
Therapist
Quantitative Study Designs
Treatment Assigned
No YesObservational Study Experimental or
Interventional StudyComparator
Randomized
No YesNo Yes
Descriptive Study
Analytical StudyNon RCT
RCT
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
TherapistTypes of Quantitative Study Designs:
Observational:Descriptive
• Case Report• Case Series
Observational:Analytical
• Cohort• Case Control• Cross
Sectional
Experimentalor
Interventional• Single Group• Parallel• Cross Over• Factorial• Withdrawal• Latin Square• Sub Groups• Pilot Groups• Group
Allocation
Randomization& Blinding
Methods to Reduce Bias inExperimental Studies:
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Other Types of Study Designs:
AuditsSurveysEconomic Analysis (Cost Analysis, Cost
Effectiveness Analysis, Cost-BenefitAnalysis, Cost-Utility Analysis)
Systematic Reviews & Meta-AnalysisNarrative Reviews
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India
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Punita V. SolankiOccupational
TherapistCommon Terms Used to Describe Studies:
LongitudinalCross SectionalProspective (Before & After Design)RetrospectiveRetrospective - ProspectiveEcologicalExplanatoryPragmaticClusterEfficacyEffectivenessRandomizationBlindingControlsPlacebo/Sham
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India
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India Observational StudyDesigns
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Observational Descriptive Study Designs
The researcher is looking atwhat is happening to a group of
people
Does the researcher have acontrol group with which to
compare these people?
IF No: ObservationalDescriptive Study Design
What is Happening in the Study?
Example: Case Report and Case Series (Useful for generating ideasfor research projects). Researcher reports what was observed in oneperson or in a group of people
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Observational Analytical Study DesignsWhat is Happening in the Study?
The researcher is looking atwhat is happening to a group
of people
Does the researcher have acontrol group with which to
compare these people?
IF YES: ObservationalAnalytical Study Design
Researcher reports the similarities and differences betweentwo or more groups of people.
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
• Something happened tothe people. Theresearcher wants toobserve the outcome.
CohortStudy
• The outcome is alreadyknown. The researcherwants to know why somepeople got this outcome.
CaseControl
Study
• The researcher alreadyknows what happened tothe people and what theoutcome was.
CrossSectional
Study
Observational Analytical Study Designs
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Cohort Study Design
PAST PRESENT FUTURE
Subjects Exposedto Risk Factor
Matched Controls NotExposed to Risk Factor
Follow UpEveryone to
See WhoGets the
Outcome
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Cohort Study Design: Example
PAST PRESENT FUTURE
Professional Computer UsersExposed to Risk of Repetitive
Reaching Tasks
Professional Computer Usersnot Exposed to Risk of
Repetitive Reaching Tasks
Follow UpEveryone toassess the
symptoms ofRepetitive
Strain Injuriesof Upper Limb
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Case Control Study Design
PAST PRESENT FUTURE
Subjects with theOutcome
Matched Controlswithout the Outcome
Look Back toSee WhichRisk FactorsThey HaveBeenExposed To.
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Case Control Study Design: Example
PAST PRESENT FUTURE
Subjects with CMCJoint OA
Matched Controlswithout CMC Joint OA
Look Back toSee Which WorkRelated RiskFactors TheyHave BeenExposed To.
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Survey: One Time Assessment.
Subjects are questioned for the presence of riskfactors and outcomes.
Useful for establishing Prevalence.
Establish Association but Not Causality.
Are cheap, simple and ethically safe.
Large study sample required.
Useful in studying rare diseases/disorders.
Cross Sectional Study Design
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
The groups can be unequal, confounders can beasymmetrically distributed and recall bias is aproblem.
Used to collect information on a Sample of thePopulation.
Special kind of Survey: Example: Census.
Academic Perspective: Can be a chosen studydesign for dissertation study [Which has limitedTime Duration for the Conduct of the Study]
Cross Sectional Study Design
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Example:
1. Prevalence of Repetitive Stress Injuries of UpperLimbs in Secondary School Children, who areComputer Users, as assessed by one timeQuestionnaire.
2. Severity of CMC Joint Osteoarthritis amongst theAdult Female Chefs Aged 20 to 40 years into dailyprofessional catering business as assessed on a onetime Questionnaire.
Cross Sectional Study Design
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Observational Study Design SelectionBased on Time Availability
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Cause to EffectStarts with ExposureTests Disease
FrequencyLarge Sample SizeLong Term Follow UpExpensiveLess Recall BiasGreater Level of
Evidence (Level: 2)Prospective
Effect to CauseStarts with DiseaseTests Cause
FrequencySmall Sample SizeShort Term Follow UpInexpensiveRecall Bias +Lower Level of
Evidence (Level: 3)Retrospective
Cohort Versus Case Control Study Designs
Cohort Study Design Case Control Study Design
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India Experimental/Interventional Study
Designs
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Punita V. SolankiOccupational
Therapist
What is happening in the study?
The researcher has introduced a treatmentto some or all of the people and is looking
at what the effects are
Were the people who received the newtreatment chosen at random?
YES No
RCT NRCT
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Single Group Study Design (Interventional Study)
Enrollment:Baseline
Treatment
Screening
Example: Population: Infants with Club Hand DeformityIntervention: Novel Club Hand SplintComparator: NoneOutcome: Functional Hand ScoreStudy Design: Single Group Study
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Parallel Groups Study Design
Enrollment:
Run In PeriodRandomization
Rx: A
Rx: B
Baseline
Example: Population: Infants with Club Hand DeformityIntervention: Novel Club Hand Splint (Rx: A)Comparator: Resting Pan Splint (Rx: B)Outcome: Functional Hand ScoreStudy Design: Parallel Group Study
13th September 20143rd Annual NationalConference of SHT,
India
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Punita V. SolankiOccupational
Therapist
Cross Over Study Design
Enrollment:
Baseline
Randomization
Wash Out Period
ScreeningRx: A
Rx: BRx: B
Rx: A
Example: Population: Male Adults with HTN & DMIntervention: Conventional Exercises (Rx: A)Comparator: Conventional Exercises with
Isokinetic Hand Training (Rx: B)Outcome: Hand Strength; Functional EnduranceStudy Design: Cross Over Study
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Parallel Versus Cross Over Study Design
Between PatientsMore VariabilityLess SensitiveMore PatientsRobustNo Wash Out PeriodNo Test Retest EffectNo Need for Stable
Disease
Within PatientsLess VariabilityMore SensitiveFewer PatientsLess RobustWash Out PeriodTest Retest EffectMust have Similar
Baseline & StableDisease
Parallel Study Cross Over Study13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Factorial Study DesignExercise Therapy +Stimulator (Rx: B)
YES Placebo B0
ExerciseTherapy +ManualTherapy(Rx: A)
YES Group IRx: A + B
Group IIRx: A + B0
PlaceboA0
Group IIIRx: A0+ B
Group IVRx: A0 + B0
E.g.: Population: Adult Industrial Male Workers with Hand InjuryIntervention: Exercise Therapy + Manual Therapy (Rx: A) &
Exercise Therapy + Placebo MT (Rx: A0)Comparator: Exercise Therapy + Stimulator (Rx: B) & Exercise
Therapy + Placebo Stimulator (Rx: B0)Outcome: Perdue Dexterity Test & the Time to Return to WorkStudy Design: Factorial Study
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India
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Factorial Study Design
E.g.: Population: Adult Industrial Male Workers with Hand InjuryIntervention: Exercise Therapy + Manual Therapy(Rx: A) &
Exercise Therapy + Placebo MT (Rx: A0)Comparator: Exercise Therapy + Stimulator (Rx: B) & Exercise
Therapy + Placebo Stimulator (Rx: B0)Outcome: Perdue Dexterity Test & the Time to Return to WorkStudy Design: Factorial Study
Enrollment: Baseline
Randomization
Run InPeriod/Screening
Rx: A + B
Rx: A0 + B0
Punita V. SolankiOccupational
Therapist
Withdrawal Study Design
Treatment A
Group I: Continued onTreatment A
Group II: WithdrawnFrom Treatment A
Advantages:• Easy access to subjects.• Show whether proven treatment remains beneficial.
Disadvantages:• Selected population.• Different stages of disease.
E.g. Population: Adults with CMC Joint OA; Intervention:Intra-articular Therapy; Comparator: Subjectswithdrawn from the study; Outcome: Effect on ArticularCartilage as assessed on MRI & Study Design:Withdrawal Study Design
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Latin Square Study Design
Example: Population: Adults with Upper Limb CRPSIntervention: Drug A (3 Formulations: 1, 2 & 3)Comparator: Drug B & C (3 Formulations: 1, 2 & 3)Outcome: Pain Assessment on VAS, Functional Score & Effecton QoL.Study Design: Latin Square Study Design
VolumeNumber
Period 1 Period 2 Period 3
1 A B C
2 B C A
3 C A B
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India
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Punita V. SolankiOccupational
Therapist
Types of Controls Used in Experimental Studies
No Control Group (Single GroupInterventional Study Design)
Experimental Studies: (Control Group AlwaysPresent)
Historical ControlsPlacebo Therapy/Sham TreatmentStandard of Care/Conventional TherapyOther Treatment Methods (To be proved
superior or inferior to the experimental noveltreatment method)
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Random Number Generation &Concealed Allocation
There are a variety of techniques to generate arandom sequence that can be used to decideallocation:
Computer random number generationRandom number tablesShuffled cards or envelopes.
This ensures that the group assignment cannot bepredicted in advance.
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Random Number Generation &Concealed Allocation
Concealment means the interventions in thedifferent arms of the study are kept secret. So theresearchers are unaware of the intervention in thegroup to which a subject will be allocated.
Advantage: It avoids both conscious &subconscious selection of patients into the study. Itprevents selection bias. A good study will havedifferent investigators recruiting and randomizingsubjects. Alternatively randomization can be doneelectronically on internet or with sealed opaqueenvelops or coded containers.
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India
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Types of RandomizationFixed Randomization: The randomization
methods are defined and allocation sequences areset up before the start of the study. E.g.: Simple,Block, Stratified & Randomized Consent. Othertypes are Quasi-Random Allocation, ClusterRandomization.
Adaptive Randomization: The randomizedgroups are adjusted as the study progresses toaccount for imbalances in the numbers in thegroups or in response to the outcome data. Anexample is minimization.
Randomization reduces:Selection Bias &
Confounding Bias
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Types of Fixed RandomizationSimple Randomization:Random assignment of
treatments per participant; independently of anyother factors.
Method: Flipping a coin (2 Groups), rolling a die(> 2 Groups), Random number tables, Computergenerated random numbers.Advantage: Simple and Practical to implement.
Disadvantage: Unequal distribution ofconfounding factors; particularly in small trials.
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Types of Fixed RandomizationBlock Randomization:Randomization within
blocks of sequential participants. Some refer tothis method as “Permuted Block Randomization”.Method: Subjects are put into blocks which whenfilled are divided equally into the different armsof the study. The order of this allocation withinthe block is randomly permuted.Advantage: Equal numbers of patients in eacharm are ensured.
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Types of Fixed RandomizationStratified Randomization: Randomization
within clusters of participants. It has better controlof potentially important prognostic factors (age,gender, race, clinical centres, geographical regionsetc.)Method: Subgroups containing confounding factorsare formed. Block randomization takes place withineach subgroup.Advantage: Confounding factors are equallydistributed in the different arms.Disadvantage: Impractical in smallstudies; so minimization is analternative method for achievingsimilarity between groups.
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Adaptive RandomizationThe probability of being allocated to a certain armin the study is adjusted to maintain similaritybetween the arms. E.g. Minimization.
Minimization:At the outset of the study it isdecided which factors would be present in equalnumbers in the different arms.
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Types of BlindingOpen Label Study.Single Blind Study. {Usually the research
participant is blinded}Double Blind Study. {The investigator and the
research participants are blinded}Triple Blind Study. {The investigator, research
participant and the statistician are blinded}
Double Blind Double Dummy
Blinding Reduces:Observation Bias &
Analysis Bias
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Level of Evidence of Various Study Designs
Punita V. SolankiOccupational
Therapist
Quiz Time
Title 1: Efficacy of pressure therapy in themanagement of hand oedema in patients with crushhand injury - A randomised controlled trial.Objective: To compare pressure therapy withconventional therapy in terms of oedemamanagement and functional improvement.
P: Patients with Crush Hand InjuryI: Pressure TherapyC: Conventional TherapyO: Reduction of Oedema and Improvement of HandFunctionS: RCT
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
Quiz Time
Title 2: Efficacy of Static Serial Versus StaticProgressive Hand Splint as an Adjunct to ExerciseTherapy in the Functional Management of PostBurn Hand Contractures : A 12 month randomisedcontrolled trial.
P: Patients with Post Burn Hand ContractureI: Static Serial Splint & Exercise TherapyC: Static Progressive Splint & Exercise TherapyO: Improvement of Hand ROM and FunctionS: RCT
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India
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Quiz TimeSay True or False:1. Randomized Controlled Trial offers the best evidence for allclinical research questionsAnswer: False
2. To study the prevalence of sports injuries amongst theschool children we should select RCT study design.Answer: False
3. Randomized Controlled Trials offer Level Ib evidence onanalysis.Answer: True
4. To study the efficacy of a novel occupational therapytreatment method we should select RCT study designAnswer: True
5. Randomization in an RCT study design reduces observationbias.Answer: False
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Quiz TimeSay True or False:6. Cohort studies are relatively cheap as compared to CaseControl studiesAnswer: False
7. Cohort studies require a small sample size as compared toCase Control studiesAnswer: False
8. The best observational study design for studying thefunctional outcome in Mucopolysaccharidosis patientsattending the genetic clinic of the hospital with an incidence of1 in 25,000 born babies, would be Case Control Study?Answer: True
9. Case Control studies are prospective study designsAnswer: False
10. Cross sectional study design is the best for studyingprevalence of any conditionAnswer: True
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Quiz TimeSelect the Best Correct Response:1. Two novel occupational therapy treatment methods werepublished independently in a journal. If we plan to comparethese two novel treatment methods in the same study for aprogressive condition, which study design would be the best?a. Withdrawal Studyb. Parallel Group Studyc. Cross Over Studyd. Factorial StudyKEY: d2. Two treatment methods are proved to be efficacious in themanagement of spine degenerative conditions independently.If we plan to compare these treatment methods which studydesign would be the best?a. Withdrawal Studyb. Parallel Group Studyc. Cross Over Studyd. Factorial StudyKEY: b
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Punita V. SolankiOccupational
Therapist
Quiz Time
Select the Best Correct Response:3. The strongest evidence for causality comes from which ofthe following research methods/designs?a. Experimentb. Case control study.c. Correlation study.d. Ethnography.KEY: a
4. An investigator takes a sample of healthy individuals,records their ongoing exposure to the treatment with novellow temperature thermoplastic splint and relates that to thesubsequent occurrence of skin irritation in the same group.a. Case-control studyb. Ecological studyc. Cohort studyd. Cross-sectional studyKEY: c
13th September 20143rd Annual NationalConference of SHT,
India
Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
Quiz TimeSelect the Best Correct Response:5 . Recall Bias is encountered in which of the followingobservational study design?a. Case Seriesb. Cohortc. Cross Sectionald. Case ControlKEY: d
6. Which of the following is an advantage of a case-controlstudy?a. There is little or no bias in assessment of exposure.b. Multiple disease outcomes following a selected exposurecan be readily studied.c. Dependence on recall by subjects in the study minimized.d. It is possible to determine the true incidence of the disease.e. It may be used to study etiology of a rare diseaseKEY: e
Punita V. SolankiOccupational
Therapist
Acknowledgements:I am extremely thankful to my mentor for criticallyreviewing my presentation & guiding me withvaluable comments to improvise on mypresentation:
• Dr. Sandeep B. Bavdekar Sir (HOD - PaediatricMedicine Department at B. Y. L. Nair Hospital & T. N.Medical College, Mumbai Central).
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Punita V. SolankiOccupational
Therapist
13th September 20143rd Annual NationalConference of SHT,
India
References:1. The Doctor’s Guide to Critical Appraisal by Dr. Narinder KaurGosall, Dr. Gurpal Singh Gosall. 3rd Edition, 2012. Published by PasTestLtd. Cheshire (UK)2. Research Methodology: A step by step guide for beginners byRanjit Kumar. 2nd Edition, 2005. Published by Pearson EducationAustralia.3. ABC of Research Methodology and Applied Biostatistics: A Primerfor Clinicians and Researchers by M. N. Parikh and Nithya Gogtay. 1st
Edition; 2009.4. Foundations of Clinical Research: Applications to Practice by LeslieGross Portney & Mary P. Watkins. 2nd Edition; 2000. Published byPrentice Hall Inc.5. Principles and Practice of Clinical Research by John I. Gallin &Frederick P. Ognibene. 2nd Edition, 2007. Published by Elsevier Inc.Burlington, MA, USA.6. Bernd Röhrig, Jean-Baptist du Prel, Daniel Wachtlin, Maria Blettner.Types of Study in Medical Research. Part 3 of a Series on Evaluation ofScientific Publications. Dtsch Arztebl Int 2009; 106(15): 262–8. DOI:10.3238/arztebl.2009.02627. Research Design: Qualitative, Quantitative and Mixed MethodsApproaches. John W. Creswell. Second Edition. 2003. SagePublications . In Chapter 1: A Framework for Design.
Presentation Time Duration:1 Hour