CPH Exam Evidence-Based Approaches to Public Health Guide With Practical Questions And Verified Answers.

2. Epidemiologists conduct observational and experimental studies. Observation of the exposure and disease status of each study participant has yielded many insights into public health, including John Snow's studies of cholera and drinking water in London, England. The two most common types of observational studies are cohort studies and case- control studies; a third type is crosssectional studies. The most effective study design for investigating the source of a waterborne disease outbreak is A. Case- control study B. Prospective cohort study C. Retrospective cohort study D. Ecological study - correct answer C. Retrospective cohort study 3. A fallacy is the use of invalid information or faulty reasoning in reaching a conclusion. Which one of the following epidemiological study designs is most prone to the fallacy of interpreting an aggregate-level association of risk factor and disease for individuals? A. Prospective cohort study B. Retrospective cohort study C. Case- control study D. Ecological study - correct answer D. Ecological study 6. Public health surveillance through screening programs are fundamental tools in public health. We use data to know where the health burdens are, to signal anomalies and health risks, and to inform actions and interventions that can keep people safer and healthier. The bias of falsely attributing greater survival to early detection of disease in a community with a screening program, compared to a community without such a program, is referred to as A. Referral bias B. Length bias C. Lead time bias D. Survival bias - correct answer C. Lead time bias 8. Diagnostic tests for diseases are often described in terms of their validity, reliability, sensitivity, and specificity. Positive predictive value is the probability that subjects with a positive screening test truly have the disease. Negative predictive value is the probability that subjects with a negative screening test truly do not have the disease. For a rare disease, the positive predictive value of a screening test increases with A. Greater disease prevalence B. Less disease prevalence C. Less specificity D. Greater scarcity - correct answer A. Greater disease prevalence 10. Experimental study designs can be expensive but they can also yield very informative data. For example, randomized clinical trials (RCTs) are studies in which the participants are randomly assigned into separate groups that compare different exposures (e.g., medical therapies). Random assignment of human participants into treatment groups reduces the likelihood of experimental bias. Nevertheless, RCTs are frequently criticized because of their A. Poor internal validity B. Poor external validity C. Inability to account for confounders D. Inability to account for self-selection - correct answer B. Poor external validity 11. A risk factor, for example, exposure to asbestos fibers, is any attribute, characteristic, or exposure of an individual that increases the likelihood of developing a disease or injury, for example, mesothelioma, a lung disease that may take a long time for symptoms to be detected. Which of the following is a measure of risk assessed from a cohort with a variable length of follow-up time? A. Incidence B. Cumulative incidence C. Incidence density D. Incidence odds - correct answer C. Incidence density 12. Epidemiologists conduct observational and experimental studies. Observation of the exposure and disease status of each study participant has yielded many insights in public health, including John Snow's studies of cholera and drinking water in London, England. The two most common types of observational studies are cohort studies and case- control studies; cross-sectional studies are also observational. An advantage of the case- control study design in comparison to prospective cohort study design is A. Can assess the natural history of disease B. Efficient for studying rare exposures C. Efficient for studying rare diseases D. Less potential for systematic errors - correct answer C. Efficient for studying rare diseases 22. In a case- control study, investigators start by enrolling a group of people already diagnosed with a disease. As a control group, the investigator then enrolls a group of people without the disease. To avoid or minimize bias, the controls from a case- control study should be selected ideally from the A. General population B. Population of healthy, nondiseased individuals C. Population from which the cases had been chosen D. Hospital setting - correct answer C. Population from which the cases had been chosen 23. Several approaches have been developed to detect and minimize bias in epidemiological study designs. For example, a matched case- control design should match pairs on A. Confounder(s) of interest B. All possible confounders C. Main effect and exposure D. Depends on other epidemiological variables - correct answer A. Confounder(s) of interest 27. Tobacco smoking is the major risk factor for lung cancer. In the United States, cigarette smoking is linked to about 80% to 90% of lung cancer deaths. Using other tobacco products, such as cigars or pipes, also increases the risk for lung cancer. Tobacco smoke is a toxic mix of more than 7,000 chemicals. Many are poisons. At least 70 are known to cause cancer in people or animals. The 80% to 90% cited is a measure of A. Cumulative incidence B. Proportionate mortality C. Case-fatality rate