You read in a health magazine about a study in which a new t

You read in a health magazine about a study in which a new therapy technique for depression was examined. A group of depressed individuals volunteered to participate in the study, which lasted 9 months. There were 50 participants at the beginning of the study and 29 at the end of the 9 months. The researchers claimed that of those who completed the program, 85% improved. What possible confounds can you identify in this study?

Solution

29 participants who completed the program were 85% improved when compared to those who left the program(21)

more than 50% benefited from the program