A researcher studied the effect of an antidepressant on...

A researcher studied the effect of an antidepressant on depression. He randomly assigned subjects with moderate levels of depression to two groups. One group received the antidepressant and the other a placebo. Subjects were blinded with respect to the treatment they received. After four weeks, the researcher interviewed all subjects and rated the change in their symptoms based on the comments of subjects during the interview. Critics said that the results were suspect because the ratings were not blind. Explain what this means and how lack of blindness could bias the reported results.

Transcript

00:01 Once again, welcome to a new problem.

00:05 This time we're dealing with experimental design.

00:13 We're dealing with experimental design.

00:16 And when it comes to experiments, when it comes to experiments, we have what you call the treatment group, the treatment group, and the control group.

00:35 So an experiment can be divided into two groups, the treatment and the control.

00:41 The treatment receives a specific intervention.

00:49 The treatment receives a specific intervention, and the control receives a placebo.

00:56 So a placebo is kind of like a fake intervention.

01:06 For the most part, experiments can either be blind or double blind.

01:13 Experiments can be blind or double blind.

01:16 Blind means that the subjects are randomly assigned.

01:25 The subjects are randomly assigned to the treatment and the control group.

01:38 And these subjects, they don't happen to be aware which group they belong.

01:44 So you know, you could be on a treatment group or you could be on a control group.

01:49 Double blind experiments means that both the subjects, the subject of the subjects and the experimenter and the experimenter are unaware of who belongs to which group.

02:24 So coming back to this problem, we have a case right here.

02:37 And in this particular problem, the research involves the studying the impact of the impact of an antidepressant, antidepressant on depression.

03:02 Antidepressant on depression.

03:06 So there are two groups right here.

03:14 And the subjects have moderate.

03:25 Moderate levels of depression.

03:32 The subjects have moderate levels of depression...