Ans. Within-subject designs comprises of the same participants for all of the experimental conditions. This is different from those designs in which different groups are taken for the different experimental conditions. Using the same participants repeatedly for the experiment involves some problems and difficulties such as boredom, fatigue and practice effects. These problems in turn affect the performance, concentration, and the accuracy of the experiment. Results can also get much improved since the participants get familiar with the task and are given the chance to practice due to the repeated measurements. The practice effects or the order effects can be minimized by counterbalancing. Different treatments are assigned in different order to the participants. For instance, half of the participants be exposed to control A and then control B, and the other half be dealt with the control B first and then control A. In this way, the results would be less impacted by practice and boredom. Loss of concentration and boredom can also be reduced by providing breaks during the experiment. These breaks help in making the participants fresh and not bored, and also help in recovering from adaptation, or habituation caused from the previous experiment. The potential for fatigue and boredom may be decreased by managing only one or two treatments per session. Practice or carryover effects must be separated from the treatment effects by making the treatment order and independent variable. Doing this offers significant knowledge regarding the size of practice effects and also can indicate the source of differences amid the results obtained from the experiments.
The advantages and disadvantages of repeated measures. (2014, September 03). Retrieved March 28, 2018, from https://dsowen.wordpress.com/2011/12/01/the-advantages-and-disadvantages-of-repeated-measures/