A school district developed an after-school math tutoring program for high school students. To assess the effectiveness of the program, struggling students were randomly selected into treatment and control groups. A pre-test was given to both groups before the start of the program. A post-test assessing the same skills was given after the end of the program. The study team determined the effectiveness of the program by comparing the average change in pre- and post-test scores between the two groups. During the course of the program, some students in both the treatment and control groups either dropped out of school or they moved away with their families. Could this attrition potentially distort the estimated effectiveness of the tutoring program? Defend your answer.