Identify which of the following six types of study designs most appropriately characterizes the situation described below.
You would like to assess the effectiveness and efficiency of delivering health services through your clinic. After selecting a 10% sample of all patient visits during the past six months, you are able to characterize the patient population who used your clinic in terms of age, race, sex, method of referral, diagnostic category, therapy provided, method of payment, daily patient load, and clinic staff work schedules.
A. Clinical trial
B. Prospective cohort study
C. Historical prospective cohort study
D. Cross-sectional study
E. Community trial
F. Case-control study