EPID600 Summer 2013 Final Exam topics

Module I. Epidemiology in public health

• Define epidemiology, know major uses, and major concepts (e.g., population, disease frequency and distribution, disease determinants, disease control)
• Be familiar with the major (broad brush) historical developments and transitions in epidemiology and public health (from A&S Introduction)
• Know the primary contribution(s) or accomplishments of major figures in the history of epidemiology (John Graunt, James Lind, William Farr, John Snow, Joseph Goldberger) (from A&S Introduction)

Module II. Studying populations

• Know what is meant by a population perspective
• Be able to identify a proportion, a rate, a ratio that is neither of these
• Know the correct use of scaling factors (e.g., "per 1,000") and units (e.g., "per year")
• Know the meaning, formula, calculation, interpretation, interrelationships, and use of key measures: crude birth rate, rate of natural increase, population growth rate, general fertility rate, total fertility rate (TFR), completed fertility, mortality rate, sex ratio, dependency ratio, and that many of these can be computed for population subgroups (e.g., age-specific, sex-specific, etc. - i.e., stratification)
• Interpret and compare population pyramids
• Interpret life expectancy measures, know what most strongly influences it
• Effects of age and sex distribution on demographic and epidemiologic measures
• Understand basic concepts of age standardization
• Know major data sources - what major kinds of information are available from a population census, vital statistics, surveillance systems, national surveys (only the basics of what is presented in A&S)

Module III. Outbreak investigation

• Identify steps in an outbreak investigation / summary slides from Dr. Weber's lecture and when they would appropriately be taken
• Interpret data collected in an outbreak investigation (e.g., the football player table that David Weber showed) to identify likely causes
• Construct / interpretation a simple epidemic curve (e.g., point source, common source, propagated)

Module IV. Measures of disease frequency

• Basic concepts of descriptive epidemiology (from A&S) - disease frequency by person, place, time
• Know difference between a fixed population (fixed cohort) and a dynamic one
• Know the meaning, formula, calculation, interpretation, interrelationships, and use of key measures: incidence rate, incidence proportion (cumulative incidence), prevalence,case fatality "rate", person-time, and that many of these can be computed for population subgroups (e.g., age-specific, sex-specific, etc. - i.e., stratification)
• Be familiar with the popcorn maker analogy
• For example questions, see the exercises at the end of the Measures of Disease Frequency chapter and the end of the Descriptive Epidemiology chapter.

Module V. Natural history / population screening

• Levels of prevention (primary, secondary, tertiary) - the definitions of these terms (as with most terms in epidemiology) are not entirely uniform, but for this class I go by our textbook's usages.
• Stages in natural history of disease: induction, incubation (infectious disease), latency
• Target for screening programs is the detectable, pre-clinical phase (DPCP).
• Challenges to evaluating screening programs: lead time bias, length bias, overdiagnosis bias
• Test reliability
• Test validity: sensitivity, specificity
• Predictive value, relation to sensitivity, specificity, and prevalence of the condition
• For example questions, see the exercises at the end of the Screening chapter in A&S.

Module VI. Study Designs - Intervention Studies

• Explain what is meant by a "community trial" and a "clinical trial", and how they differ.
• Be familiar with a causal comparison in terms of the counterfactual model and substitute population.
• Differentiate experimental studies from observational studies.
• Describe and recognize major epidemiologic study designs: intervention trial, cohort, case-control, cross-sectional, and ecologic (aggregate-level) designs.
• List advantages and disadvantages of intervention trials in epidemiology.
• Describe the purpose of randomization and its relation to the counterfactual model and substitute population.
• Explain what is meant by a placebo and the "placebo effect".
• Explain the purpose of masking ("blinding") in an intervention trial.
• Appreciate the importance of study size for statistical power and precision.
• Describe an intent-to-treat analysis of data from a randomized trial and list its advantages and disadvantages.
• Explain the purpose of compliance measures.
• Explain what is meant by "equipoise" and its significance for the ethics of an intervention trial.

Module VII. Study Designs - Cohort Studies

• Explain the concept of a weighted averages; calculate and interpret them.
• Explain the purpose of age-adjustment (e.g., age standardization) and be able to reason about the differences between crude and adjusted measures.
• Differentiate an open (dynamic) cohort from a fixed cohort that is not closed, from a closed cohort; classify a cohort from a description.
• Describe the purpose and characteristics of a cohort study, its strengths, and its weaknesses for studying different kinds of diseases (e.g., common vs. rare, acute vs. long latency) and exposures.
• Use basic epidemiologic measures of occurrence and association and recognize the various terms used to refer to them: incidence proportion (risk, cumulative incidence), person-time, incidence rate (incidence density, hazard), relative risk (risk ratio, rate ratio, hazard ratio), risk difference, rate difference, monotonic (dose-response).
• Calculate and interpret the above epidemiologic measures from data or algebraically.
• Define the concept of attributable risk and know how to interpret basic epidemiologic measures of impact: attributable risk (absolute impact, exposed persons), population attributable risk (absolute impact, full population), attributable risk proportion (relative impact, exposed person), population attributable risk proportion (relative impact, full population)
• Identify epidemiologic measures being used in a study, regardless of the terms used (or mis-used) to describe them;
• Interpret tables and figures from a cohort study.

Module VIII: Study Designs - Case-Control Studies

• Explain the advantages and disadvantages of using incidence rates versus mortality rates for etiologic research.
• Attributable risk (see Cohort studies module)
• Describe the characteristics of a case-control study and explain its principal advantages and disadvantages for studying different kinds of diseases (e.g., common vs. rare, acute vs. long latency) and exposures.
• Correctly use the term "study base" or "source population" and explain its relation to the control group in a case-control study.
• Identify the study base in relation to methods of cases ascertainment (e.g., from a disease registry, acute outbreak).
• Explain the relation between incidence rate and incidence proportion.
• Recognize and interpret "odds" and "odds ratio" and know how to calculate them from data and to interpret them.
• Identify when the odds ratio (OR) is a good estimate of the rate ratio and/or the risk ratio.
• Create a 2 x 2 table from data or a study description.
• Explain and analyze statements about the above concepts from an article.

Module IX. Error - Selection and Information Bias

• Identify the major sources of error in epidemiological studies.
• Differentiate between internal and external validity.
• Discuss sources of variability and threats to validity in published or planned epidemiologic research studies.
• Describe selection bias and differentiate it from lack of generalizability.
• Give examples of selective forces on study populations and how they can be reduced or eliminated from epidemiological studies.
• Differentiate among the external, target, actual, and study populations.
• Differentiate information bias from selection bias.
• List major sources of information bias in given epidemiologic studies and ways to control them.
• Distinguish between differential and non-differential misclassification bias, explain how their effects on a given study may differ, and describe ways to reduce differential misclassification bias specifically.
• Identify and evaluate the potential for information bias associated with the methods for assessing exposures and outcomes in epidemiologic studies.
• Recognize information bias, differential misclassification bias, and nondifferential misclassification bias in an actual study.
• Quantify the effect of bias on measures of association.

Module X. Multicausality: Confounding

• Explain what is meant by confounding bias.
• State the criteria to consider a covariate to be a confounder.
• Distinguish between potential confounders and actual confounders.
• Explain when a potential confounder would not be controlled for as a confounder.
• Distinguish between a crude and an adjusted measure of association.
• Use crude and adjusted measures to determine whether confounding is present.
• Describe methods to control for confounding in both the design and analysis of a study, and cite their advantages and disadvantages.
• Apply concepts to a case study.

Module XI: Data Analysis and Interpretation

• List the primary factors that affect p-values and confidence intervals.
• List the primary determinants of statistical power and describe its importance for epidemiologic studies.
• Identify incorrect interpretations of P-values and confidence intervals; know how to correctly interpret these measures.
• Describe the relations of sample size to p-values, confidence intervals, and statistical power.
• Describe the steps in managing and conducting basic analyses of data collected in an epidemiologic study.
• Construct a 2 x 2 table from information in text and compute basic epidemiologic measures from that table.
• Explain the basic concept behind meta-analysis of epidemiologic study results and interpret the results of a published meta-analysis.

Module XII: Broader Perspectives on Epidemiology in Public Health

• Describe basic ethical principles in conducting research on humans and the requirements for informed consent.
• Know major milestones in the history of development of U.S. and international human research regulations.
• See epidemiology and public health from a broader context.
• List major public health problems that are largely neglected by the field of epidemiology.
• Give examples of how awareness and behavior are fundamental determinants of public health and environmental quality.
• Give examples of conflicts between economic incentives and public health.
• Recognize examples of how physical, chemical, biological, social, and environmental factors can influence thinking, emotions, behavior, and health.
• Give examples of how basic human tendencies may interfere with collective action to protect public health.
• Suggests ways that epidemiology can contribute to the solution of fundamental problems in public health and human ecology.
• Example question:
        The 3 basic elements of the informed consent process are: (Choose one best answer)
              A. information, comprehension, voluntariness
              B. respect for persons, beneficence, and justice
              C. information, documentation, limitation of liability
              D. compensation, information, voluntariness