CHAPTER 7 Having Designs on Study Design 87

Chapter 7

Having Designs on

Study Design

B

iostatistics can be seen as the application of a set of tools to answer ques-

tions posed through human research. When studying samples, these tools

are used in conjunction with epidemiologic study designs in such a way as

to facilitate causal inference, or the ability to determine cause and effect. Some

study designs are better than others at facilitating causal inference. Nevertheless,

regardless of the study design selected, an appropriate sampling strategy and sta-

tistical analysis that complements the study design must be used in conjunction

with it.

In this chapter, we provide an overview of epidemiologic study designs and pres-

ent them in a hierarchy so that you can relate them to the biostatistical approaches

described in the different chapters of this book. We start by looking at broad study

design categories such as observational, experimental, descriptive, and analytic,

and move into descriptive study designs including expert opinion, case studies

and case series, ecological (correlational) studies, and cross-sectional studies. We

present analytic study designs next  — case-control studies and longitudinal

cohort studies — which are superior to descriptive designs in terms of developing

evidence for causal inference, and then move into the highest-level designs: sys-

tematic reviews and meta-analyses.

IN THIS CHAPTER»

» ^{Grasping the hierarchy of study}

designs in epidemiology»

» ^{Appreciating relative strength of}

different study designs for causal

inference»

» ^{Getting the details about different}

study designs