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Case Study 2 on Experimental/Causal Comparative Designs: Forming Experimental and Control Groups in a Study of Drug Prevention1

Problem:
Researchers wanted to evaluate a family-participation drug prevention program in the Boys and Girls Clubs.  Four clubs were purposively selected to receive the program because they had directors who would strongly support the promotion of family involvement and would give the program coordinator the flexibility to work in nontraditional ways to encourage family participation.  This created a problem:  A true experimental design could not be used because the program clubs were not selected at random.

A Solution:
Other Boys and Girls Clubs that were similar on socioeconomic and other demographic variables to the family-participation program clubs were selected as comparison groups.

A Drawback to the Solution:
Children in the family-participation program were about a quarter of a year younger, on the average, than those in the comparison groups.  While all groups were predominantly African American, there were differences in the second most frequent racial/ethnic groups with differences in the Hispanic and Caucasian mix.  There were differences in the gender composition of the groups (e.g., 35% female in the family-participation clubs and 41% female in the control clubs).

Your Opinions:

  1. Is the use of purposively selected clubs (rather than randomly selected clubs) a limitation of the study?  Why or why not?
  2. If you answered “yes” to question 1, how serious is the limitation?
  3. Overall, do you believe the solution is better than nothing (that is, not having a control or comparison group)?  Why or why not?
  4. Are there other possible solutions that might help solve the problem?  What are they?

1Source/Reference:  St. Pierre, T.L., Mark, M.M., Kaltreider, D.L., & Aikin, K.J.  (1997)  Involving parents of high-risk youth in drug prevention:  A three-year longitudinal study in Boys and Girls Clubs.  Journal of Early Adolescence, 17, 21-50. 

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