Grace randomly assigns college-bound African-American students to the intervention or to a control condition. Grace gives a mathematics achievement test in September to both groups. Through the academic year the treatment condition receives the intervention. She uses end of year achievement tests to see whether there are differences between conditions. Grace found that students studied together for the end of year achievement tests. She believes that some of the students in the treatment condition shared intervention information with the control group. Which of the following threats does Grace now have to be most concerned about?
A) Maturation by treatment
B) Treatment diffusion
C) Selection by treatment
D) Statistical regression

Question

Quizplus · Accepted Answer

Grace now has to be most concerned about treatment diffusion, which occurs when participants in the control group receive some or all of the intervention. This can lead to reduced differences between groups, making it more difficult to establish a causal effect of the intervention.

Grace Randomly Assigns College-Bound African-American Students to the Intervention or to a Control