Table of Contents vii

Determining how many participants to enroll in a clinical trial. . . 68

Assembling the study protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Carrying Out a Clinical Trial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Protecting clinical trial participants. . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Collecting and validating data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Analyzing Your Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Dealing with missing data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Handling multiplicity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

CHAPTER 6: Taking All Kinds of Samples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Making Forgivable (and Non-Forgivable) Errors. . . . . . . . . . . . . . . . . . . 78

Framing Your Sample. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Sampling for Success . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Taking a simple random sample. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Taking a stratified sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Engaging in systematic sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Sampling clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Sampling at your convenience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Sampling in multiple stages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

CHAPTER 7: Having Designs on Study Design. . . . . . . . . . . . . . . . . . . . . . . 87

Presenting the Study Design Hierarchy. . . . . . . . . . . . . . . . . . . . . . . . . . 88

Describing what we see. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Getting analytical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Going from observational to experimental. . . . . . . . . . . . . . . . . . . . 90

Climbing the Evidence Pyramid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Starting at the base: Expert opinion. . . . . . . . . . . . . . . . . . . . . . . . . . 91

Making the case with case studies. . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Making statements about the population. . . . . . . . . . . . . . . . . . . . . 92

Going from case series to case-control. . . . . . . . . . . . . . . . . . . . . . . 93

Following a cohort over time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Advancing to the clinical trial stage. . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Reaching the top: Systematic reviews and meta-analyses. . . . . . . 97

PART 3: GETTING DOWN AND DIRTY WITH DATA . . . . . . . . . . 99

CHAPTER 8: Getting Your Data into the Computer. . . . . . . . . . . . . . 101

Looking at Levels of Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Classifying and Recording Different Kinds of Data. . . . . . . . . . . . . . . . 103

Dealing with free-text data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Assigning participant study identification (ID) numbers. . . . . . . . . . 104

Organizing name and address data in the study ID crosswalk. . . 104

Collecting categorical data in your research database . . . . . . . . . 105