Grace conducts research on race and achievement in mathematics. She designs a study to see if a new intervention she designed increases African-American students' math achievement scores. She goes to a local school with a representative Aftrican-American student population and 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 if there are differences between conditions.
-Which of the following external validity threats should most concern Grace regarding her study?
A) Selection
B) History
C) Instrumentation
D) Maturation

Question

Quizplus · Accepted Answer

The biggest external validity threat in this study is selection bias. By randomly assigning only college-bound African-American students, Grace is limiting the generalization of her findings to only that specific population. The results may not be applicable to all African-American students or to other ethnic groups.

Grace Conducts Research on Race and Achievement in Mathematics