Copyright © 2012 Wolters Kluwer Health Lippincott Williams.docx

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams
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Chapter 9
Quantitative Research Design
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Question
Tell whether the following statement is true or false:
Many qualitative nursing studies aim to elucidate cause-and-
effect relationships.
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Answer
False
Many quantitative not qualitative nursing studies aim to
elucidate cause-and-effect relationships.

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Question
Counterfactual is what would have happened to the same people
simultaneously exposed and not exposed to the causal factor.
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Answer
True
Counterfactual is what would have happened to the same people
simultaneously exposed and not exposed to the causal factor.
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The Counterfactual MethodThe counterfactual is what would
have happened to the same people simultaneously exposed and
not exposed to the causal factor.Effect represents the difference
between the two.
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CausalityThe counterfactual methodCriteria for causality—
Lazarsfeld (1955)
1. Temporal
2. Empirical relationship
3. Relationship cannot be explained as
being caused by a third variable
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Experiments or Randomized Controlled Trial Properties
Manipulation
Control
Randomization
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ManipulationDoing something to study
participantsExperimenter manipulates the independent variable
by administering a treatment (intervention) to some subjects and
withholding it from others, or by administering some other
treatment.
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Control GroupResearchers can expose the control group to
various conditions:
– No treatment
– Alternative treatment
– Placebo
– Standard treatment
– Different doses of the treatment
– Wait list
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Randomization (Random Assignment or Random
Allocation)Involves placing subjects into treatment conditions
at randomApproximates the ideal—but impossible—
counterfactual of having the same people in multiple treatment
groups simultaneouslyBasic randomization
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Question
Some studies involve patient-centered interventions that are

tailored to meet individual needs or characteristics.
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Answer
True
Everyone in the experimental group usually gets the same
intervention as delineated in formal protocols, but some studies
involve patient-centered interventions (PCIs) that are tailored to
meet individual needs or characteristics.
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Small Table of Random Digits
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Example of Random Assignment Procedure
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StratificationDivided into groups before randomizedPermuted
block randomization
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BlindingSingle-blind studiesDouble-blind studies
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RandomizationClusterPartially randomized patient preference
designRandomized consent design
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Experimental DesignsAfter-only (posttest-only) designBefore–
after (pretest–posttest) designFactorial designCrossover
(repeated measures) design
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Symbolic Representation of a Pretest–Posttest Experimental
Design
R O1 X O2
R O1 O2
R = Randomization
O = An observation or measurement
X = An intervention
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Factorial DesignsTwo or more variables are manipulated
simultaneously.Test both main effects and interaction
effectsRandomized block designCrossover design
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Quasi-Experimental and
Preexperimental Designs
Nonequivalent control group pretest–posttest design (quasi-
experimental)
O1 X O2
O1 O2
Nonequivalent control group posttest-only design
(preexperimental)
X O1
O1

One group pretest-posttest design (preexperimental)
O1 X O2
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Quasi-Experimental DesignsTime series designNonequivalent
control group before–after
design
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Time Series Design
O1 O2 O3 O4 X O5 O6 O7 O8
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Other Quasi-Experimental DesignsQuasi-experimental dose-
response analysisQuasi-experimental (nonrandomized) arms of a
PRPP randomization design
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Nonexperimental/Observational ResearchDescriptive
researchCorrelational studies
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Designs of Correlational StudiesRetrospective (case-control)
designProspective (cohort) designsNatural experimentsPath
analytic studies
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Descriptive StudiesPrevalence studiesIncidence studies

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Topic: Corporate citizenship displayed within the company
TOMS
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Chapter 10
Rigor and Validity in
Quantitative Research
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Validity and Validity ThreatsValidity: the approximate truth of
inferenceThreats to validity are reasons that an inference could
be wrong.
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Types of ValidityStatistical conclusion validityInternal
validityConstruct validityExternal validity

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Controlling Intrinsic Source
of Confounding
VariabilityRandomizationCrossoverHomogeneityStratification/b
lockingMatching (pair matching)Statistical control
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Benefits and Limitations of Control Methods: Randomization
Benefits:Controls all preintervention confounding variablesDoes
not require advance knowledge of which variables to control
Limitations:Ethical and practical constraints on variables that
can be manipulatedPossible artificiality of conditions
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Benefits and Limitations of Control Methods: Crossover

(Repeated Measures)
Benefits:If done with randomization, strongest possible
approach
Limitations:Cannot be used if there are possible carryover
effects from one condition to anotherHistory threat may be
relevant if external factors change over time.
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Benefits and Limitations of Control Methods: Homogeneity
Benefits:Easy to achieve in all types of researchEnhances
interpretability of relationships
Limitations:Limits generalizabilityRequires knowledge of which
variables to controlRange restriction could lower statistical
conclusion validity.
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Benefits and Limitations of Control Methods: Stratification
Benefits:Enhances the ability to detect and interpret
relationshipsOffers opportunity of examining blocking variable
as an independent variable
Limitations:Usually restricted to a few stratifying
variablesRequires knowledge of which variables to control

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Benefits and Limitations of Control Methods: Matching
Benefits:Enhances interpretability of relationshipsMay be easy
if there is a large “pool” of potential available controls
Limitations:Usually restricted to a few matching
variablesRequires knowledge of which variables to matchMay
be difficult to find comparison group matches, especially if
there are more than two matching variables
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Benefits and Limitations of Control Methods: Statistical Control
Benefits:Enhances ability to detect and interpret
relationshipsRelatively economical means of controlling several
confounding variables
Limitations:Requires knowledge of which variables to control,
as well as measurement of these variablesRequires some
statistical sophistication
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Four Types of Validity Affect
Rigor of Quantitative StudyStatistical conclusion
validityInternal validityConstruct validityExternal validity
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Statistical Conclusion ValidityLow statistical powerRestriction
of rangeUnreliable implementation of a treatment
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Intervention FidelityExtent to which the implementation of a
treatment is faithful to its plan
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Internal ValidityTemporal
ambiguitySelectionHistoryMaturationMortality/attritionTesting
and instrumentation
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Construct ValidityConcerns inferences from the particular
exemplars of a study to the higher order constructs that they are
intended to represent
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Threats to Construct ValidityReactivity to the study
situationsResearcher expectanciesNovelty effectsCompensatory
effectsTreatment diffusion
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External ValidityConcerns inferences about the extent to which
relationships observed in a study hold true over variations in
people, conditions, and setting as well as over variations in
treatments and outcomes
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Threats to External ValidityInteraction between relationship and
peopleInteraction between causal effects and treatment variation
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Trade-Offs and Priorities in Study ValidityInternal and external
validityPrioritization and design decisions
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RE-AIM
FrameworkReachEfficacyAdoptionImplementationMaintenance
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Chapter 12
Sampling in Quantitative Research
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Question
The aggregate of cases in which a researcher is interested is
called a sample.
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Answer
False
The aggregate of cases in which a researcher is interested is
called a population. A sample is selection of a portion of the
population to represent the entire population.
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Basic Sampling Concepts in Quantitative Studies
Population: the aggregate of cases in which a researcher is
interested
Sampling: selection of a portion of the population (a sample) to
represent the entire population
Element: basic population unit about which information is
collected
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Eligibility CriteriaEstablish population characteristics
Determine participation in studyMaximize construct
validityInclusionExclusion
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Question
Researchers usually sample from the target population.
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Answer
False
Researchers usually sample from the accessible population but
should identify the target population to which they want to
generalize their results.
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Basic Sampling Concepts in Quantitative Studies
Representative sample
A sample whose key characteristics closely approximate those
of the population

Sampling bias
The systematic over- or underrepresentation of segments of the
population on key variables
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Question
Probability sampling involves random selection of elements.
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Answer
True
Probability sampling involves random selection of elements.
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Basic Sampling Concepts in Quantitative Studies (cont.)
Probability sampling
Involves random selection of elements
Nonprobability sampling
Does not involve selection of elements at random

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Nonprobability SamplingConvenience sampling Snowball
sampling Quota samplingConsecutive samplingPurposive
sampling
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Probability SamplingSimple random samplingStratified random
samplingMultistage samplingCluster samplingSystematic
sampling
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Power AnalysisEstimate sample sizeLarge samples preferred to
small samples

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Chapter 11
Specific Types of
Quantitative Research
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Question
Phase I clinical trials involve seeking opportunities for
refinements and preliminary evidence of efficacy.
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Answer
False
Phase II clinical trials involve seeking opportunities for
refinements and preliminary evidence of efficacy. Phase I
features of the intervention that are finalized.

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Clinical TrialsEffectiveness of clinical interventionsPhase
IPhase IIPhase IIIPhase IV
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Sequential Clinical TrialData from paired “mini-
experiments”Continuously analyzedPreference
measuresStopping rules
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Question
Practical clinical trials aim to reduce the gap between efficacy
and effectiveness studies.
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Answer
False
Practical clinical trials are designed to provide information to
clinical decision makers.

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Practical Clinical TrialsAlso called pragmatic clinical
trialsProvide information to clinical decision makers
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Evaluation ResearchEffectiveness of a program, policy,
procedure Assist decision makers
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Question
What is the purpose of an outcome analysis?
Describes the status of some condition after the introduction
of a program
Tests whether a program causes net impacts
Describes the process by which a program gets implemented and
functions in practice
Assesses whether the monetary costs of a program are
outweighed by benefits
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Answer
A
Outcome analysis describes the status of some condition after
the introduction of a program.
Impact analysis tests whether a program causes net impacts.

Process analysis describes the process by which a program gets
implemented and functions in practice.
Cost analysis assesses whether the monetary costs of a program
are outweighed by benefits.
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Various AnalysesProcess or implementationOutcomeImpactCost
or economicCost–benefit analysisCost-effectiveness
analysisCost-utility analysis
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Question
Outcome research examines the quality and effectiveness of
health care and nursing services.
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Answer
True
Outcome research examines the quality and effectiveness of
health care and nursing services.
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Outcome ResearchQuality and effectiveness of health care and
nursing servicesHealth care qualityStructureProcessClient risk
factorsOutcomes
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Survey ResearchPeople’s characteristics, behaviors, and
intentions by asking them to answer questionsPersonal
interviewsTelephone interviewsQuestionnaires
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Secondary AnalysisResearchers analyze previously collected
data.EconomicalDifficult to identify appropriate existing data
base
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Needs AssessmentNeeds of group or communityThree main
needsKey informantSurveyIndicators approach
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Question

The Delphi technique is a method of problem solving in which
one round of questionnaires are sent to a panel of experts.
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Answer
False
The Delphi technique is a method of problem solving in which
several rounds of questionnaires are sent to a panel of experts,
not one round.
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Delphi TechniqueProblem solvingSeveral rounds of
questionnaires
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Replication StudiesIdenticalVirtualSystematic extension
replication
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Methodologic StudiesDevelopmentValidationAssessment
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