Describe two ways in which contamination may have influenced the results of this study.

Question

What will be an ideal response?

Answer 1

314) A researcher was interested in determining whether more frequent breaks (i.e., "coffee breaks") in a business setting would help employees to be more productive. With the cooperation of the management, employees on one floor of the corporate offices were allowed to take a 10-minute break each hour (at any time) between 8:00 and 11:00 A.M. (for a total of 30 minutes). The comparison group comprised employees on different floors who followed the usual corporate policy of taking a 30-minute break sometime during the morning (at any time). Measures of productivity were gathered for each employee according to his or her job (e.g., number of reports written, number of sales made, etc.). A time series analysis was applied to compare the productivity of both groups of employees for six months before and after the intervention (started in July). Quite surprisingly, the productivity of both groups increased following the onset of the intervention, suggesting to the researcher that the timing of breaks makes no difference.
Contamination may have affected the results through rivalry or diffusion of treatment. Employees in the comparison group may have been worried that their performance data would not compare well to that of employees in the treatment group, and may have increased their performance so as not to look bad. Diffusion of treatment may have occurred if employees in the comparison group learned that others were taking more frequent breaks and decided to take more frequent breaks also.