Sampling Design and Procedure
Cluster sampling was used to sample physical therapy students in the United States. The United States was divided into four regions, Northeast, Southeast, Northwest and Southwest. From each of these regions, two physical therapy programs were randomly selected to which the Hospital Anxiety and Depression Scale and other accompanying checklists designed to measure anxiety and depression were sent. Each school selected was telephoned and asked if they were willing to participate in the study. None of the schools selected declined to participate, so no further sampling was necessary. The goal was to survey 8 physical therapy schools and receive at least 300 responses (the total number of students enrolled all together in the eight schools was 334), at three different times during the first semester, and at least 3 different times during the 3rd semester. This translates into the first semester for students enrolled in their first year of the physical therapy program and the third semester for students in their second year of the physical therapy program.
It was hoped that an 80% response rate would be achieved from this same cohort of students. Three hundred students is a comparable number of subjects to similar studies performed using medical students. Packets were sent to the director of each physical therapy program and administered to first and second year students in Fall 2001, the first day of class or orientation, 1-2 weeks before midterms, and 1 week before finals. Each director was asked to make the telephone number of the on-campus psychological services available at that school in the event that participation in the study elicited a stress response.
