62 PART 2 Examining Tools and Processes

Identifying aims, objectives, hypotheses,

and variables

The aims or goals of a clinical trial are short general statements (often just one

statement) of the overall purpose of the experiment. For example, the aim of an

experiment may be “to assess whether drinking green tea every day improves

alertness in older adults.”

The objectives are much more specific than the aims. In a clinical trial, the objec-

tives usually refer to the effect of the intervention (treatment being tested) on

specific outcome variables at specific points in time in a group of a specific type of

study participants. In a drug trial, which is a type of experimental clinical research,

an efficacy study may have many individual efficacy objectives, as well as one or

two safety objectives, while a safety study may or may not have efficacy

objectives.

When designing a clinical trial, you should identify one or two primary objectives —

those that are most directly related to the aim of the study. This makes it easier to

determine whether the intervention meets the objectives once your analysis is

complete. You may then identify up to several dozen secondary objectives, which

may involve different variables or the same variables at different time points or in

different subsets of the study population. You may also list a set of exploratory

objectives, which are less important, but still interesting. Finally, if testing a risky

intervention (such as a pharmaceutical), you should list one or more safety

objectives (if this is an efficacy study) or some efficacy objectives (if this is a

safety study).

The objectives you select will determine what data you need to collect, so you have

to choose wisely to make sure all data related to those objectives can be collected

in the timeframe of your study. Also, these data will be processed from various

sources, including case report forms (CRFs), surveys, and centers providing labo-

ratory data. These considerations may limit the objectives you choose to study!

Drug clinical trials are usually efficacy studies. Here is an example of each type of

objectives you could have in an efficacy study:»

» ^{Primary efficacy objective: To compare the effect of new hypertension}

(HTN) drug XYZ, relative to old drug ABC, on changes in systolic blood

pressure (SBP) from baseline to week 12, in participants with HTN.»

» ^{Secondary efficacy objective: To compare the effect of HTN drug XYZ,}

relative to drug ABC, on changes in serum total cholesterol and serum

triglycerides from baseline to weeks 4 and 8, in participants with HTN.