Sampling & Generalization

Psychologists almost never study everyone they are interested in. The entire group a researcher wants to draw conclusions about is called the target population, and the smaller group actually studied is the sample. The goal of sampling is to obtain a group that is representative of the population so that findings can be generalized back to it. When a sample is unrepresentative, it is said to be biased, and conclusions drawn from it may not apply to the wider population. Understanding sampling and the different forms of validity is essential for judging how much trust to place in any study.

Several sampling techniques exist, each with strengths and weaknesses. Random sampling gives every member of the target population an equal chance of selection, for example by drawing names from a comple