Foundations of Clinical Research: Applications to Practice

913 Pages·2015·48.56 MB·English

by  Leslie G. Portney DPT PhD FAPTA

Foundations
of Clinical Research
Applications to Practice
3rd Edition
Leslie G. Portney, DPT, PhD, FAPTA
Dean, School of Health and Rehabilitation Sciences
MGH Institute of Health Professions
Boston, Massachusetts
Mary P. Watkins, DPT, MS
Professor Emerita
MGH Institute of Health Professions
Boston, Massachusetts
F.A.DavisCompany
1915ArchStreet
Philadelphia,PA19103
www.fadavis.com
Copyright©2015byF.A.DavisCompany
Copyright©2015byF.A.DavisCompany.Allrightsreserved.Thisbookisprotectedby
copyright.Nopartofitmaybereproduced,storedinaretrievalsystem,ortransmittedinany
formorbyanymeans,electronic,mechanical,photocopying,recording,orotherwise,without
writtenpermissionfromthepublisher.
PrintedintheUnitedStatesofAmerica
Lastdigitindicatesprintnumber:10987654321
Asnewscientificinformationbecomesavailablethroughbasicandclinicalresearch,
recommendedtreatmentsanddrugtherapiesundergochanges.Theauthor(s)andpublisher
havedoneeverythingpossibletomakethisbookaccurate,uptodate,andinaccordwith
acceptedstandardsatthetimeofpublication.Theauthor(s),editors,andpublisherarenot
responsibleforerrorsoromissionsorforconsequencesfromapplicationofthebook,andmake
nowarranty,expressedorimplied,inregardtothecontentsofthebook.Anypracticedescribed
inthisbookshouldbeappliedbythereaderinaccordancewithprofessionalstandardsofcare
usedinregardtotheuniquecircumstancesthatmayapplyineachsituation.Thereaderis
advisedalwaystocheckproductinformation(packageinserts)forchangesandnew
informationregardingdoseandcontraindicationsbeforeadministeringanydrug.
Cautionisespeciallyurgedwhenusingneworinfrequentlyordereddrugs.
LibraryofCongressControlNumber: 2014960189
Authorizationtophotocopyitemsforinternalorpersonaluse,ortheinternalorpersonaluse
ofspecificclients,isgrantedbyF.A.DavisCompanyforusersregisteredwiththeCopyright
ClearanceCenter(CCC)TransactionalReportingService,providedthatthefeeof$.25percopy
ispaiddirectlytoCCC,222RosewoodDrive,Danvers,MA01923.Forthoseorganizationsthat
havebeengrantedaphotocopylicensebyCCC,aseparatesystemofpaymenthasbeen
arranged.ThefeecodeforusersoftheTransactionalReportingServiceis:
8036-4657-5/140+$.25.
To
My teachers and mentors
who opened so many doors
Jane Carlin
Beverly Devine
Bob Lamb
Sol Levine
Eugene Michaels
Otto Payton
Freda Rebelsky
Steve Rose
Cathy Perry Wilkinson
and especially Mom and Dad
Skip, Devon and Lindsay
Who teach me the meaning of it all every day.
P
-LG
To my students who became colleagues
and my colleagues who became students­
From all of you, I have learned
how to direct this book to the real world of clinical research.
Thank you.
-MPW

Contents
Preface xv
Acknowledgments xvii
Reviewers xix
PART I FOUNDATIONS OF CLINICAL RESEARCH 1
1 A Concept of Clinical Research 3
Defining Clinical Research 3
Measurement of Outcomes 4
Models of Health and Disability 6
Evidence-Based Practice 8
Sources of Knowl edge 11
Types of Research 18
The Research Process 23
Understanding Method, Content and Philosophy 25
Commentary: Research and Evidence-Based Practice: Investigation vs. Clinical
Decision Making 26
2 The Role of Theory in Clinical Research 33
Purposes of Theories 33
Components of Theories 35
Development of Theories 38
Characteristics of Theories 39
Theory and Research 40
Theory and Law 44
Commentary: Applying Theory 44
v
vi
CONTENTS
Ethical Issues in Clinical Research 47
3
Integrity of the Researcher 47
The Protection of Human Rights in Clinical Research 48
The Institutional Review Board 52
Elements of Informed Consent 53
Commentary:
A Patient Care Perspective 58
PART II CONCEPTS OF MEASUREMENT 61
4 Principles of Measurement 63
Quantification and Measurement 64
The Indirect Nature of Measurement 64
Rules of Measurement 66
Commentary:
Do I Really Care about the Level of Measurement? 72
5 Reliability of Measurements 77
Measurement Error 77
Reliability Coefficients 82
Types of Reliability 84
Generalizability 91
Pilot Testing 94
Commentary:
What Is the True Score? 94
6 Validity of Measurements 97
Validity and Reliability 97
Validity of Inferences 98
Face Validity 99
Content Validity 101
Criterion-Related Validity 102
Construct Validity 105
Measuring Change 109
Criterion Referencing and Norm Referencing 113
Cross-Validation 114
Commentary:
The Ongoing Pursuit of Validity 115
PART Ill DESIGNING CLINICAL RESEARCH 119
7 Asking the Research Question 121
Selecting a Topic 122
The Research Problem 123
vii
CONTENTS
Importance and Feasibility of the Research Question 126
Target Population 128
The Research Rationale 128
Variables 129
Research Objectives 133
Reviewing the Literature 136
Commentary: Putting the Horse before the Cart 138
8 Sampling 143
Populations and Samples 143
Sampling Techniques 146
Probability Sampling 148
Nonprobability Sampling 154
Recruitment 156
Commentary: Sampling, Like Life, Is a Compromise 157
9 Validity in Experimental Design 161
Characteristics of Experiments 162
The Research Protocol 165
Blinding 170
Design Strategies for Controlling Intersubject Differences 171
Threats to Validity 174
The CONSORT Statement 186
Commentary: The Relative Validity of Evidence 187
10 Experimental Designs 193
Clinical Trials 193
Design Classifications 194
Selecting a Design 194
Designs for Independent Groups 196
Repeated Measures Designs 206
Sequential Clinical Trials 213
Efficacy vs. Effectiveness 218
Commentary: Matching the Research Question and Design 220
11 Quasi-Experimental Designs 223
One-Group Designs 223
Multigroup Designs 228
Commentary: Generalization to the Real World 232
12 Single-Subject Designs 235
Structure of Single-Subject Designs 236
The Target Behavior 239
viii CONTENTS
Reliability 241
Experimental Control: Limitations of the A-B Design 242
Withdrawal Designs 242
Multiple Baseline Designs 246
Designs with Multiple Treatments 251
Data Analysis in Single-Subject Research 254
Generalization of Findings 268
Commentary:
Documenting Wisely 271
13 Exploratory Research: Observational Designs 277
Retrospective and Prospective Research 278
Longitudinal and Cross-Sectional Research 279
Correlation and Prediction 280
Case-Control Studies 282
Cohort Studies 286
Evaluating Causality in Observational Studies 289
Methodological Research: Reliability and Validity 290
Historical Research 292
Secondary Analysis 294
Commentary:
Advantages and Disadvantages of Exploratory Research 296
14 Descriptive Research 301
Developmental Research 302
Normative Studies 304
Qualitative Research 306
Descriptive Surveys 313
Case Studies 314
Commentary:
First Things First 318
15 Surveys and Questionnaires 325
Interviews and Questionnaires 325
Design of Surveys 327
Constructing Survey Questions 332
Scales 338
Q-Sort 348
Delphi Survey 349
Analysis of Survey Data 350
Informed Consent 351
Commentary:
They Have a Thousand and One Uses 352
16 Systematic Reviews and Meta-Analysis 357
Study Objective: Asking the Question 360
Selection Criteria 361
CONTENTS ix
Search Strategy 364
Evaluating Methodologic Quality 365
Meta-Analysis 371
Appraisal of Systematic Reviews and Meta-Analyses 376
Find Out More 376
Commentary:
A Guide for the Future 378
PART IV DATA ANALYSIS
383
17 Descriptive Statistics 385
Frequency Distributions 385
Measures of Central Tendency 390
Measures of Variability 391
The Normal Distribution 399
Commentary:
Description Is an Essential Beginning 403
18 Statistical Inference 405
Probability 405
Sampling Error 408
Confidence Intervals 411
Hypothesis Testing 416
Type I Error: Level of Significance 419
Type II Error: Statistical Power 421
Concepts of Statistical Testing 424
Parametric versus Nonparametric Statistics 429
Commentary:
Statistical Significance versus
Clinical Significance 429
19 Comparing Two Means: The Test 433
t-
The Conceptual Basis for Comparing Group Means 433
t-
The Test for Independent Samples 437
Thet -Test for Paired Samples 445
Inappropriate Use of Multiplet-Tests 447
Commentary:
The Significance of Significance 449
20 Comparing More Than Two Means: Analysis of Variance 451
Analysis of Variance for Independent Samples:
One-Way Classification 451
Analysis of Variance: Two-Way Classification 458
Analysis of Variance: Three-Way Classification 467
Repeated Measures Analysis of Variance 467
Commentary:
Beyond Analysis of Variance 476