Sampling

  Your Scenario: You are commissioned to determine the effectiveness of TF-CBT in the state of Michigan on reducing behavior and trauma symptoms in children with trauma as measured by two standardized instruments, the Child Behavior Checklist and Trauma Symptom Checklist. There are 4000 trained TF-CBT therapists currently practicing in the state of Michigan, and each therapist has 10 completed cases that you would have available to you for data collection. (We are assuming you have all the approvals and consents to have access to this data). Your goal is to as accurately as possible represent cases from different therapists throughout the state, and to be sure to represent those who see small numbers of minority ethnic/religious pods in a couple areas of the state, too. What is your sampling plan, answering the following questions. You have a limited budget, and someone would have to collect the data from the sample you have devised, so you must be quite conservative and be aware of limited resources. 1.Define the Population of Interest 2.Identify a Sampling Frame, and how you determined it 3.Select a Sampling Method 4.Determine a Sample Size; describe why you selected this sample size based on power analysis and effect size. 5. If not already addressed above, how will you be sure you capture a good cross-section of gender, race, and ethnic characteristics, as well as not be overweighted by urban children (as there are more therapists concentrated in the urban areas)?