. When should you use a between subjects design, and when should you use a within subjects design? Give two reasons for each, and explain.

Question

What will be an ideal response?

Answer 1

Ans: When looking at experiments, there are two basic types: between subjects designs and within subjects designs. A between subjects design occurs when the conditions are distributed across participants. Each participant participates in only one condition. The approach is used because the researcher is concerned that participating in more than one condition would contaminate the results. Another reason for using this design is when participating in more than one condition would cause a burden for the participants—too much time or too much energy. Another reason is that the impact of a given condition could not be isolated. Further, the between subjects approach reduces the likelihood that participants will guess the hypothesis of the research. On the other hand, a within subjects design means that participants participate in more than condition. Researchers often select this type of design when there is little likelihood of carryover from one condition to another—or there are such effects that carry over and the researcher actually wants to study them. Carryover might mean that we want to study whether the effect of a therapy lingers when you go back to baseline—or not.