Fall Semester 2026–2027 MPH – Master of Public
Health (MPH) Updated 2026 | 190+ Questions and
Answers | MPH Comprehensive Study Guide, Practice
Exam, Exam Prep Test Bank, Epidemiology,
Biostatistics, Environmental Health, Global Health,
Health Policy & Management, Social & Behavioral
Sciences, Community Health, Program Planning &
Evaluation, Health Promotion, Evidence-Based Public
Health, Detailed Rationales and Complete Revision
Material
Question 1: In the context of epidemiological research, which study design is
most susceptible to the ecologic fallacy, where associations observed at the
group level may not hold true at the individual level?
A. Case-control study
B. Cross-sectional study
C. Ecologic study
D. Randomized controlled trial
CORRECT ANSWER: C. Ecologic study
Rationale: The ecologic fallacy is a fundamental limitation of ecologic studies. In these
designs, data are collected on populations or groups rather than individuals. An
association seen between exposure and disease rates at the group level (e.g., per capita
fat consumption and national breast cancer rates) may not reflect the exposure-disease
relationship at the individual level. This is due to confounding and the inability to link
exposure and outcome for the same person. This fallacy does not apply to case-control,
cross-sectional, or RCTs, as they collect individual-level data.
Question 2: A new screening test for a rare but aggressive cancer has a
sensitivity of 95% and a specificity of 90%. The prevalence of the disease in the
target population is 1%. What is the positive predictive value (PPV) of this
test?
A. 8.8%
B. 50.0%
C. 90.0%
D. 95.0%
CORRECT ANSWER: A. 8.8%
Rationale: PPV is calculated as (Sensitivity x Prevalence) / [(Sensitivity x Prevalence) +
((1-Specificity) x (1-Prevalence))]. Using these values: (0.95 x 0.01) / [(0.95 x 0.01) +
(0.10 x 0.99)] = 0.0095 / (0.0095 + 0.099) = 0..1085 = 0.0876, or approximately
8.8%. Despite the test’s high sensitivity and specificity, the low prevalence of the disease
results in a low PPV, meaning most positive test results will be false positives.
,Question 3: The World Health Organization (WHO) defines health as a state of
complete physical, mental, and social well-being. This definition is considered
a cornerstone of public health philosophy primarily because it:
A. Focuses solely on the absence of disease and infirmity.
B. Emphasizes that health is a fundamental human right and is influenced by social
determinants.
C. Provides a purely biomedical model for understanding disease.
D. Is universally accepted and has never been subject to criticism.
CORRECT ANSWER: B. Emphasizes that health is a fundamental human right
and is influenced by social determinants.
Rationale: The WHO's 1948 definition was revolutionary because it moved beyond the
narrow biomedical model (which focuses on disease) and explicitly recognized the
importance of mental and social well-being. This holistic view implies that health is not
just an individual responsibility but a product of social, economic, and environmental
factors. This underpins the public health focus on social determinants and health equity.
It is not universally accepted without criticism, as some argue it is overly utopian.
Question 4: In a cohort study, what is the most critical threat to the study's
internal validity when the loss to follow-up is differential between the exposed
and unexposed groups?
A. Information bias
B. Selection bias
C. Confounding
D. Random error
CORRECT ANSWER: B. Selection bias
Rationale: Differential loss to follow-up is a primary source of selection bias in cohort
studies. If participants with a specific exposure and outcome are more likely to be lost
from the study than others, the association measured at the end of the study will be
systematically distorted. This differs from information bias (misclassification of
exposure/outcome) and confounding (which is a mixing of effects from a third variable).
The bias stems from which individuals are retained in the analysis, affecting the study's
internal validity.
Question 5: Which of the following core public health functions is BEST
exemplified by the collection and analysis of data on the incidence of
foodborne illnesses to detect an outbreak?
A. Assurance
B. Policy Development
C. Assessment
D. Evaluation
CORRECT ANSWER: C. Assessment
,Rationale: The three core functions of public health are Assessment, Policy
Development, and Assurance. Assessment refers to the systematic collection, analysis,
and monitoring of health data to identify health problems and priorities in a community.
Investigating a foodborne illness outbreak through data collection and analysis is a
classic example of assessment. Policy development involves using this data to formulate
policies, and assurance refers to ensuring these services are available to the population.
Question 6: A study aims to investigate the association between a genetic
polymorphism and a rare disease. Which study design would be the most
efficient and powerful for this purpose?
A. Prospective cohort study
B. Retrospective cohort study
C. Case-control study
D. Community trial
CORRECT ANSWER: C. Case-control study
Rationale: Case-control studies are particularly efficient for studying rare diseases.
Because they begin by identifying existing cases and then look back at their exposure
history, they can enroll a sufficient number of cases without needing to follow a massive
cohort for many years. This makes them more cost-effective and faster than cohort
studies for rare outcomes. Community and cohort trials are not the most efficient
designs for studying rare diseases with genetic risk factors.
Question 7: The "prevention paradox," as described by Geoffrey Rose, refers to
the phenomenon where:
A. A preventive measure that brings large benefits to the community offers little benefit
to each participating individual.
B. Treating high-risk individuals is always more effective than population-wide
interventions.
C. The population's health is not improved by universal screening programs.
D. The benefits of prevention are always outweighed by its harms.
CORRECT ANSWER: A. A preventive measure that brings large benefits to the
community offers little benefit to each participating individual.
Rationale: Geoffrey Rose's prevention paradox states that for many common diseases, a
large number of people at small risk may generate more cases than a small number of
people at high risk. Therefore, a population-based intervention that is effective for the
whole population may only provide a small, often imperceptible, benefit to each
individual. This creates a paradox where the intervention is highly beneficial for the
community but is not attractive to individuals, making implementation challenging.
Question 8: What is the primary purpose of conducting a systematic review
and meta-analysis in public health?
, A. To replace the need for primary research on a topic.
B. To provide a narrative summary of a topic for a general audience.
C. To summarize evidence quantitatively and objectively to inform evidence-based
practice.
D. To identify a single definitive answer to a public health question.
CORRECT ANSWER: C. To summarize evidence quantitatively and objectively
to inform evidence-based practice.
Rationale: A systematic review systematically searches for, appraises, and synthesizes all
relevant studies on a specific question. A meta-analysis is a statistical technique used in
a systematic review to combine the results of multiple studies into a single, more precise
estimate of the effect. Their primary purpose is to provide a rigorous, objective
summary of the existing evidence to guide evidence-based decision-making in policy
and practice. They do not replace primary research but help synthesize it.
Question 9: A public health intervention is designed to reduce childhood
obesity. Which of the following strategies represents a "downstream" rather
than an "upstream" approach?
A. Implementing a tax on sugar-sweetened beverages.
B. Creating a municipal policy to build more safe parks and playgrounds in low-income
neighborhoods.
C. Providing a one-on-one counseling session with a nutritionist for an obese child.
D. Regulating food marketing aimed at children on television.
CORRECT ANSWER: C. Providing a one-on-one counseling session with a
nutritionist for an obese child.
Rationale: In public health, upstream approaches focus on the root causes of health
problems (e.g., social, economic, and environmental policies), while downstream
approaches focus on treating individuals after they have developed the health issue.
Providing individual-level counseling is a downstream intervention. Taxation, policy
changes for parks, and regulating food marketing are all upstream or midstream
interventions designed to create healthier environments for the entire population.
Question 10: In a cross-sectional study, researchers find a strong positive
association between current alcohol consumption and the prevalence of
depression. Which of the following is the most serious limitation in
interpreting this finding as causal?
A. The study is too expensive to conduct.
B. The direction of the association cannot be determined (temporality).
C. The sample size was too small.
D. The study is prone to recall bias.
CORRECT ANSWER: B. The direction of the association cannot be determined
(temporality).
Health (MPH) Updated 2026 | 190+ Questions and
Answers | MPH Comprehensive Study Guide, Practice
Exam, Exam Prep Test Bank, Epidemiology,
Biostatistics, Environmental Health, Global Health,
Health Policy & Management, Social & Behavioral
Sciences, Community Health, Program Planning &
Evaluation, Health Promotion, Evidence-Based Public
Health, Detailed Rationales and Complete Revision
Material
Question 1: In the context of epidemiological research, which study design is
most susceptible to the ecologic fallacy, where associations observed at the
group level may not hold true at the individual level?
A. Case-control study
B. Cross-sectional study
C. Ecologic study
D. Randomized controlled trial
CORRECT ANSWER: C. Ecologic study
Rationale: The ecologic fallacy is a fundamental limitation of ecologic studies. In these
designs, data are collected on populations or groups rather than individuals. An
association seen between exposure and disease rates at the group level (e.g., per capita
fat consumption and national breast cancer rates) may not reflect the exposure-disease
relationship at the individual level. This is due to confounding and the inability to link
exposure and outcome for the same person. This fallacy does not apply to case-control,
cross-sectional, or RCTs, as they collect individual-level data.
Question 2: A new screening test for a rare but aggressive cancer has a
sensitivity of 95% and a specificity of 90%. The prevalence of the disease in the
target population is 1%. What is the positive predictive value (PPV) of this
test?
A. 8.8%
B. 50.0%
C. 90.0%
D. 95.0%
CORRECT ANSWER: A. 8.8%
Rationale: PPV is calculated as (Sensitivity x Prevalence) / [(Sensitivity x Prevalence) +
((1-Specificity) x (1-Prevalence))]. Using these values: (0.95 x 0.01) / [(0.95 x 0.01) +
(0.10 x 0.99)] = 0.0095 / (0.0095 + 0.099) = 0..1085 = 0.0876, or approximately
8.8%. Despite the test’s high sensitivity and specificity, the low prevalence of the disease
results in a low PPV, meaning most positive test results will be false positives.
,Question 3: The World Health Organization (WHO) defines health as a state of
complete physical, mental, and social well-being. This definition is considered
a cornerstone of public health philosophy primarily because it:
A. Focuses solely on the absence of disease and infirmity.
B. Emphasizes that health is a fundamental human right and is influenced by social
determinants.
C. Provides a purely biomedical model for understanding disease.
D. Is universally accepted and has never been subject to criticism.
CORRECT ANSWER: B. Emphasizes that health is a fundamental human right
and is influenced by social determinants.
Rationale: The WHO's 1948 definition was revolutionary because it moved beyond the
narrow biomedical model (which focuses on disease) and explicitly recognized the
importance of mental and social well-being. This holistic view implies that health is not
just an individual responsibility but a product of social, economic, and environmental
factors. This underpins the public health focus on social determinants and health equity.
It is not universally accepted without criticism, as some argue it is overly utopian.
Question 4: In a cohort study, what is the most critical threat to the study's
internal validity when the loss to follow-up is differential between the exposed
and unexposed groups?
A. Information bias
B. Selection bias
C. Confounding
D. Random error
CORRECT ANSWER: B. Selection bias
Rationale: Differential loss to follow-up is a primary source of selection bias in cohort
studies. If participants with a specific exposure and outcome are more likely to be lost
from the study than others, the association measured at the end of the study will be
systematically distorted. This differs from information bias (misclassification of
exposure/outcome) and confounding (which is a mixing of effects from a third variable).
The bias stems from which individuals are retained in the analysis, affecting the study's
internal validity.
Question 5: Which of the following core public health functions is BEST
exemplified by the collection and analysis of data on the incidence of
foodborne illnesses to detect an outbreak?
A. Assurance
B. Policy Development
C. Assessment
D. Evaluation
CORRECT ANSWER: C. Assessment
,Rationale: The three core functions of public health are Assessment, Policy
Development, and Assurance. Assessment refers to the systematic collection, analysis,
and monitoring of health data to identify health problems and priorities in a community.
Investigating a foodborne illness outbreak through data collection and analysis is a
classic example of assessment. Policy development involves using this data to formulate
policies, and assurance refers to ensuring these services are available to the population.
Question 6: A study aims to investigate the association between a genetic
polymorphism and a rare disease. Which study design would be the most
efficient and powerful for this purpose?
A. Prospective cohort study
B. Retrospective cohort study
C. Case-control study
D. Community trial
CORRECT ANSWER: C. Case-control study
Rationale: Case-control studies are particularly efficient for studying rare diseases.
Because they begin by identifying existing cases and then look back at their exposure
history, they can enroll a sufficient number of cases without needing to follow a massive
cohort for many years. This makes them more cost-effective and faster than cohort
studies for rare outcomes. Community and cohort trials are not the most efficient
designs for studying rare diseases with genetic risk factors.
Question 7: The "prevention paradox," as described by Geoffrey Rose, refers to
the phenomenon where:
A. A preventive measure that brings large benefits to the community offers little benefit
to each participating individual.
B. Treating high-risk individuals is always more effective than population-wide
interventions.
C. The population's health is not improved by universal screening programs.
D. The benefits of prevention are always outweighed by its harms.
CORRECT ANSWER: A. A preventive measure that brings large benefits to the
community offers little benefit to each participating individual.
Rationale: Geoffrey Rose's prevention paradox states that for many common diseases, a
large number of people at small risk may generate more cases than a small number of
people at high risk. Therefore, a population-based intervention that is effective for the
whole population may only provide a small, often imperceptible, benefit to each
individual. This creates a paradox where the intervention is highly beneficial for the
community but is not attractive to individuals, making implementation challenging.
Question 8: What is the primary purpose of conducting a systematic review
and meta-analysis in public health?
, A. To replace the need for primary research on a topic.
B. To provide a narrative summary of a topic for a general audience.
C. To summarize evidence quantitatively and objectively to inform evidence-based
practice.
D. To identify a single definitive answer to a public health question.
CORRECT ANSWER: C. To summarize evidence quantitatively and objectively
to inform evidence-based practice.
Rationale: A systematic review systematically searches for, appraises, and synthesizes all
relevant studies on a specific question. A meta-analysis is a statistical technique used in
a systematic review to combine the results of multiple studies into a single, more precise
estimate of the effect. Their primary purpose is to provide a rigorous, objective
summary of the existing evidence to guide evidence-based decision-making in policy
and practice. They do not replace primary research but help synthesize it.
Question 9: A public health intervention is designed to reduce childhood
obesity. Which of the following strategies represents a "downstream" rather
than an "upstream" approach?
A. Implementing a tax on sugar-sweetened beverages.
B. Creating a municipal policy to build more safe parks and playgrounds in low-income
neighborhoods.
C. Providing a one-on-one counseling session with a nutritionist for an obese child.
D. Regulating food marketing aimed at children on television.
CORRECT ANSWER: C. Providing a one-on-one counseling session with a
nutritionist for an obese child.
Rationale: In public health, upstream approaches focus on the root causes of health
problems (e.g., social, economic, and environmental policies), while downstream
approaches focus on treating individuals after they have developed the health issue.
Providing individual-level counseling is a downstream intervention. Taxation, policy
changes for parks, and regulating food marketing are all upstream or midstream
interventions designed to create healthier environments for the entire population.
Question 10: In a cross-sectional study, researchers find a strong positive
association between current alcohol consumption and the prevalence of
depression. Which of the following is the most serious limitation in
interpreting this finding as causal?
A. The study is too expensive to conduct.
B. The direction of the association cannot be determined (temporality).
C. The sample size was too small.
D. The study is prone to recall bias.
CORRECT ANSWER: B. The direction of the association cannot be determined
(temporality).
