Question

A researcher would like to conduct an experiment to test the effectiveness of a program designed to raise SAT scores. He wishes to obtain a sample of low-scoring high school students, administer the program, and then administer the SAT again. He hypothesizes that SAT scores will be higher after the program than before. Describe the ONE threat to internal validity that you think/perceive to be the most difficult to identify, correct or avoid. Please explain your answer.

Answer 1

The threat to validity is sample selection.

The program effectiveness is designed for checking the increase in SAT score and not only scores of children who are scoring low. The idea is an overall increase in SAT scores. Hence, the sample should not only include low scoring high school students, but also, medium scoring and high scoring high school students to identify if the program is effective for every child. Our aim is to make good into better and better into best.