Relative costs and statistical power in the extreme groups approach

The relationship between variables in applied and experimental research is often investigated by the use of extreme (i.e., upper and lower) groups. Recent analytical work has provided an extreme groups procedure that is more powerful than the standard correlational approach for all values of the correlation and extreme group size. The present article provides procedures to optimize power by determining the relative number of subjects to use in each of two stages of data collection given a fixed testing budget.The opinions or assertions contained herein are those of the writers and are not to be construed as official or reflecting the views of the Navy Department.Edward F. Alf, Jr. is also affiliated with the Department of Psychology, San Diego State University.     

Visual recognition memory for binary pictures: another look

Recognition memory for matrices of 0s and 1s was examined as a function of the number of elements (complexity) and density of those elements within the matrix. It was found that with greater density and lesser complexity, recognition performance improved. This result contradicts an earlier finding of Green and Purohit, who concluded that the more complicated matrices led to better performance. The present study suggests that their conclusion was erroneous and stemmed from failure to control the physical parameters of density and number of elements in the matrix. Implications for the general problem of recognition memory and eye movements are discussed.     

Using Self-Supervision to Maintain Counseling Skills: A Review

Counselor education literature acknowledges the difficulty of skill maintenance but offers few solutions. A review of related areas was conducted to provide direction in developing maintenance strategies. Four domains were considered: maintenance in behavior modification, behavioral self-control, the traditional maintenance mechanisms of feedback, supervision, and observational media, and self-supervisory programs. A self-supervisory program that applies the procedures of behavioral self-control to specific helping behavior that is identifiable on audiotape or videotape is advocated.