Suppose 100 clients referred for substance abuse problems receive new Intervention A and another receive treatment as usual (TAU).Suppose further that 20% of the recipients of Intervention A recidivate as compared to 50% of the TAU recipients.The odds ratio would be:
A)2.5.
B)4.0.
C).40.
D).20.

Question

Quizplus · Accepted Answer

The odds ratio is calculated as (ad/bc), where a is the number of clients who recidivated in the Intervention A group, b is the number who did not recidivate in the Intervention A group, c is the number who recidivated in the TAU group, and d is the number who did not recidivate in the TAU group. Plugging in the numbers given, we get (20/80) / (50/50) = 0.25/1 = 0.25. Simplifying further, 0.25 = (1/4). Therefore, the odds of recidivism are four times higher in the TAU group than in the Intervention A group. So the odds ratio is 4.0.

Suppose 100 Clients Referred for Substance Abuse Problems Receive New