Reading Graphs in Research
Read the following description of single-case research carefully and then answer the questions that follow.
A sports psychologist is hired by a college to help its basketball team get back on a winning track. The psychologist meets with the coach to plan a series of treatments designed to improve the players' performance and the team's morale. One of the behaviors selected for improvement is frequency of taking "good shots." Specifically, the coach thinks that a major problem with her team is the tendency of the players to take low percentage shots rather than show patience in waiting for a higher percentage shot opportunity. The psychologist decides to work with the three starting players with the lowest overall field goal percentages: Beth, Carol, and Arlene. The dependent variable is the proportion of high percentage shots taken during practice scrimmages during a 3-week period prior to the beginning of the season. The psychologist decides that the reinforcer for behavior change will be a visual record of a player's performance posted on the door of a player's locker after each practice session. The psychologist uses a multiple-baseline across subjects design to assess the effectiveness of this motivational technique. Results are shown in the figures. The session in which treatment was started for each player is indicated on the x-axis using the word "treatment." The pictures are attached.
1. Does visual inspection of the data in this hypothetical study provide evidence for the effectiveness of the treatment? Why or why not?
2. Based on your reading of the brief outline of this study, what is one reasonable explanation for why changes in the baselines might be observed prior to the introduction of treatment?
3. A critical reviewer of this study would likely want information regarding the degree of interobserver reliability.
1) What are two suggestions you might make in order to help ensure high observer reliability in this situation?
2)How specifically might information about interobserver reliability be obtained using a percent agreement measure?
A social scientist was hired by a local police department to evaluate the effectiveness of a program aimed at reducing juvenile delinquency in the community. When the psychologist arrived, the program had already begun. It included a three-pronged educational campaign directed at parents, community residents, and adolescents attending local schools. Public service messages appeared on television and radio; police officers and social workers made personal appearances in school classrooms; and police officers went door to door in the highest crime areas to help educate residents about community resources for troubled teens. The program lasted six weeks.
1. What type of program evaluation has the social scientist been asked to conduct?
2. Describe how a quasi-experimental design, specifically a simple time-series design, might be used by the scientist as part of the program evaluation. Be sure to provide details regarding relevant procedures and measures for this type of design.
3. Discuss the major threats to internal validity associated with the design that you have outlined.
4. The internal validity of a simple time-series design can be strengthened by including a nonequivalent control group.
a. Suggest a possible control group that the social scientist might consider in this situation.
b. Identify what measures must be obtained from the control group.