Chapter 11 Review Questions and Exercises
1. Briefly sketch an experimental design for testing a new intervention in your fieldwork agency or in another social work agency with which you are familiar. Then conduct a qualitative (open-ended, semi-structured) interview with one or two direct-service practitioners and an administrator in that agency, asking them how feasible it would be to carry out your study in their agency.
2. What potential threats to the validity of the findings can you detect in the following hypothetical design? In a residential treatment center containing four cottages, the clinical director develops a new intervention to alleviate behavior problems among the children residing in the four cottages. The center has four therapists, each assigned to a separate cottage. The clinical director selects two cottages to receive the new intervention. The other two will receive the routine treatment. To measure outcome, the clinical director assigns a social work student whose field placement is at the center to spend an equal amount of time at each cottage observing and recording the number of antisocial behaviors each child exhibits and the number of antisocial statements each makes.
3. Briefly sketch a nonequivalent comparison groups design for evaluating the effectiveness of a parent education program for parents at high risk for child abuse. What would you do to assure the readers of your study that the threat of a selectivity bias seems remote? Include in your sketch a description of the dependent variable and when and how it would be measured.
4. Identify six things you would do to avoid or alleviate practical pitfalls in carrying out the above study.
5. Briefly sketch a multiple time-series design to evaluate the effectiveness of a statewide job-training program for welfare recipients. Explain how it provides adequate control for history, passage of time, statistical regression, and selection biases.
6. Briefly sketch a case-control design to generate hypotheses about interventions that may be the most helpful in preventing teen runaways. What are the background variables that would be most important to control for? Identify and explain three uncontrolled threats to the validity of your study that would represent major reasons why the results would be exploratory only.
Chapter 11 InfoTrac/Internet Exercises
1. Use InfoTrac College Edition to find an experiment that evaluated the effectiveness of a social work intervention. How well did it control for the additional threats to validity discussed in this chapter? What efforts did it make to alleviate attrition? Were its measurement procedures obtrusive or unobtrusive? Do they appear to be free from serious bias? Also critique the study’s external validity—either positively or negatively.
2. Use InfoTrac College Edition to find a study that used a pre-experimental design to evaluate the outcome of a social work intervention. Critique the study’s internal validity—and discuss whether it had value despite its pre-experimental nature.
3. In this chapter, we looked briefly at the problem of “placebo effects.” On the web, find a study in which the placebo effect figured importantly. Briefly summarize the study, including the source of your information. (Hint: You might want to do a search using the term placebo as a key word.)
4. Use InfoTrac College Edition to find a study that used a nonequivalent comparison groups design to evaluate the effectiveness of a social work intervention. How well did it control for selection biases?
5. Use InfoTrac College Edition to find a study that used a simple or multiple time-series design to evaluate the effectiveness of a social work intervention. How well did it control for history, maturation or passage of time, statistical regression, and selection biases?
6. Use InfoTrac College Edition to find a study that used a case-control design to test or generate hypotheses about effective social work intervention with some problem. Critique the validity of the study, identifying its strengths as well as weaknesses.
7. Use InfoTrac College Edition to find a study that used a cross-sectional design to test or generate hypotheses about effective social work intervention with some problem. Critique the validity of the study, identifying its strengths as well as weaknesses.