David Johnson

Block 3 Doctoring Practice Questions 1. Which one of the following correctly lists the steps in the progression of epidemiologic reasoning? a. Conduct study, suspect association, formulate hypothesis, evaluate for causality b. Formulate hypothesis, conduct study, suspect association, evaluate for causality c. Suspect association, conduct study, formulate hypothesis, evaluate for causality d. Suspect association, formulate hypothesis, conduct study, evaluate for causality e. Suspect association, formulate hypothesis, evaluate for causality, conduct study 2. The major difference between an experiment and an observational study is: a. Bias is eliminated only in an experimental study b. Observational studies but not experiments may be referred to as ‘clinical trials’ c. Only experiments can be used to test hypotheses d. The investigator or study protocol assigns ‘exposure’ to the subjects only in an experiment e. The investigator or study protocol assigns ‘outcome’ to the subjects only in an observational study 3. What is the defining feature of a case-control study? a. Cases and controls are selected or classified on the basis of exposure & followed forward in time b. Cases are selected who have the disease, controls are identified and then both have their exposure status determined c. Subjects are given a drug (cases) or placebo (controls) and followed forward in time d. Subjects are selected for the study regardless of disease or exposure status; both attributes are then measured simultaneously e. The exposure of interest must not have occurred at the time you begin the study 4. Which of the following is a characteristic feature of case-control studies? a. Incidence rates can be calculated b. Investigators must always collect all new data because they can never use existing records c. Multiple diseases can be studied at the same time d. Rare diseases can be studied e. They are a more expensive type of study because many subjects are needed 5. A small sample of young women with clear cell adenocarcinoma of the vagina were identified (n=11) and a group of comparison young women (n=44) are selected. They were asked whether or not they had been exposed in utero to diethylstilbestrol (DES). The study explains that in the 1950s and 60s pregnant women were prescribed DES as a treatment for threatened miscarriage. Among those with vaginal cancer, 9 reported in utero exposure to DES while 4 of those without vaginal cancer reported exposure. Draw a 2x2 table for