CPH Exam Study Guide Questions and
Answers 100% Pass
Endemic - ✔✔a situation in a community where theres consistently elevated risk of
disease: malaria in Africa
Epidemic - ✔✔an increase in the number of cases of disease in a community, above
expectation in the same geographic area at the same time
Pandemic - ✔✔a worldwide epidemic
Case reports and series - ✔✔Descreptive: alert people of new illness, reports of people
with disease
Cross Sectional - ✔✔D: studies that include people who representation population. Not
selected based on disease or exposure. Identifies prevalence of either exposure or illness
in a group
Ecological - ✔✔D: describes population
case control - ✔✔selected based on disease and then go back, good for RARE cases with
long latency periods
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,cohort - ✔✔based on exposure
Relative Risk Equation - ✔✔risk of outcome in exposed/ risk of outcome in non-
exposed (A/A+B)/(C/C+D)
Odds ratio - ✔✔odds of outcome in exposed (A/B) divided by odds of outcome in
nonexposed (C/D)::: ie, AD/BC
What does it mean when RR or OR is greater than 1? - ✔✔Exposure increases risk of
outcome. Risk or odds in the exposed is greater than risk or odds in non-exposed.
What does it mean when RR or OR is less than 1? - ✔✔Exposure decreases risk of
outcome. Exposure is protective.
What does it mean when RR or OR is equal to 1? - ✔✔No association between exposure
and outcome
Bias towards the null hypothesis - ✔✔hides an association that actually exists or makes
the association appear weaker
Bias away from null - ✔✔Bias that can lead to the belief that there is an association
when there is none
Types of Observation Bias - ✔✔Recall, interviewer, misclassification
Confounding Factor - ✔✔Third variable that is associated with both the exposure and
outcome which distorts findings
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,What are things done to prevent confounding? - ✔✔1. Randomization, 2. Restriction (so
if confounded is income, exposure is smoking, outcome is lung cancer then restrict
study to participants in the same income category), 3. Matching, 4. Standardization, 5.
Stratification (creating separate tables of disease by exposure for each possible
combination of confounders), 6. Multivariable analysis
What is effect modification? - ✔✔Clarifies association (Ex: smokers exposed to asbestos
have a higher rate of lung cancer)
After you stratify based on your confounder, if your variable is only a confounder, what
will your crude and stratum-specific OR/RR look like? - ✔✔Crude OR/RR will be
greater than or less than all stratum-specific
After you stratify based on your confounder, if your variable is only an effect modifier,
what will your crude and stratum-specific OR/RR look like? - ✔✔Crude OR/RR will be
within range of stratum-specific OR/RR. stratum-specific OR/RR will be significantly
different.
After you stratify based on your confounder, if your variable is both an effect modifier
and confounded, what will your crude and stratum-specific OR/RR look like? -
✔✔Crude OR/RR will be outside range of stratum-specific OR/RR. stratum-specific
OR/RR will be significantly different.
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, Name Hill's Criteria and give short explanation - ✔✔1. Analogy (can find a similar
relationship btwn another exposure/disease 2. Coherence. considers entire picture of
association btwn exposure and outcome across different models 3. Reversibility. "If an
individual is longer exposed, does disease diminish?" 4. Specificity. One exposure
should cause one disease 5. Plausibility: Is there a model that can explain the association
6. Strength of association 7. Consistency 8. Biological Gradient. Dose response
relationship 9. Temporality. Exposure must come before disease
What is sensitivity and its' formula? - ✔✔the ability of a test to correctly identify people
with a disease (% of people who test positive out of all those who have disease)
What is specificity and its' formula? - ✔✔the ability of a test to correctly identify people
without disease (% of people who test negative out of all those who don't have disease)
Who are false negative individuals? - ✔✔People who have disease but test negative
Who are false positive individuals? - ✔✔People who don't have disease but test positive
How is Positive Predictive Value calculated? (PPV) - ✔✔number of people who test
positive who actually have disease (true positive) / number of positive tests
If cutoff value is too low, what happens to sensitivity? - ✔✔Everything above cutoff is
considered true positive, so sensitivity would go up
Disclaimer: Original Content, No Copyright Infringement, All Rights Reserved © 2025 4
Answers 100% Pass
Endemic - ✔✔a situation in a community where theres consistently elevated risk of
disease: malaria in Africa
Epidemic - ✔✔an increase in the number of cases of disease in a community, above
expectation in the same geographic area at the same time
Pandemic - ✔✔a worldwide epidemic
Case reports and series - ✔✔Descreptive: alert people of new illness, reports of people
with disease
Cross Sectional - ✔✔D: studies that include people who representation population. Not
selected based on disease or exposure. Identifies prevalence of either exposure or illness
in a group
Ecological - ✔✔D: describes population
case control - ✔✔selected based on disease and then go back, good for RARE cases with
long latency periods
Disclaimer: Original Content, No Copyright Infringement, All Rights Reserved © 2025 1
,cohort - ✔✔based on exposure
Relative Risk Equation - ✔✔risk of outcome in exposed/ risk of outcome in non-
exposed (A/A+B)/(C/C+D)
Odds ratio - ✔✔odds of outcome in exposed (A/B) divided by odds of outcome in
nonexposed (C/D)::: ie, AD/BC
What does it mean when RR or OR is greater than 1? - ✔✔Exposure increases risk of
outcome. Risk or odds in the exposed is greater than risk or odds in non-exposed.
What does it mean when RR or OR is less than 1? - ✔✔Exposure decreases risk of
outcome. Exposure is protective.
What does it mean when RR or OR is equal to 1? - ✔✔No association between exposure
and outcome
Bias towards the null hypothesis - ✔✔hides an association that actually exists or makes
the association appear weaker
Bias away from null - ✔✔Bias that can lead to the belief that there is an association
when there is none
Types of Observation Bias - ✔✔Recall, interviewer, misclassification
Confounding Factor - ✔✔Third variable that is associated with both the exposure and
outcome which distorts findings
Disclaimer: Original Content, No Copyright Infringement, All Rights Reserved © 2025 2
,What are things done to prevent confounding? - ✔✔1. Randomization, 2. Restriction (so
if confounded is income, exposure is smoking, outcome is lung cancer then restrict
study to participants in the same income category), 3. Matching, 4. Standardization, 5.
Stratification (creating separate tables of disease by exposure for each possible
combination of confounders), 6. Multivariable analysis
What is effect modification? - ✔✔Clarifies association (Ex: smokers exposed to asbestos
have a higher rate of lung cancer)
After you stratify based on your confounder, if your variable is only a confounder, what
will your crude and stratum-specific OR/RR look like? - ✔✔Crude OR/RR will be
greater than or less than all stratum-specific
After you stratify based on your confounder, if your variable is only an effect modifier,
what will your crude and stratum-specific OR/RR look like? - ✔✔Crude OR/RR will be
within range of stratum-specific OR/RR. stratum-specific OR/RR will be significantly
different.
After you stratify based on your confounder, if your variable is both an effect modifier
and confounded, what will your crude and stratum-specific OR/RR look like? -
✔✔Crude OR/RR will be outside range of stratum-specific OR/RR. stratum-specific
OR/RR will be significantly different.
Disclaimer: Original Content, No Copyright Infringement, All Rights Reserved © 2025 3
, Name Hill's Criteria and give short explanation - ✔✔1. Analogy (can find a similar
relationship btwn another exposure/disease 2. Coherence. considers entire picture of
association btwn exposure and outcome across different models 3. Reversibility. "If an
individual is longer exposed, does disease diminish?" 4. Specificity. One exposure
should cause one disease 5. Plausibility: Is there a model that can explain the association
6. Strength of association 7. Consistency 8. Biological Gradient. Dose response
relationship 9. Temporality. Exposure must come before disease
What is sensitivity and its' formula? - ✔✔the ability of a test to correctly identify people
with a disease (% of people who test positive out of all those who have disease)
What is specificity and its' formula? - ✔✔the ability of a test to correctly identify people
without disease (% of people who test negative out of all those who don't have disease)
Who are false negative individuals? - ✔✔People who have disease but test negative
Who are false positive individuals? - ✔✔People who don't have disease but test positive
How is Positive Predictive Value calculated? (PPV) - ✔✔number of people who test
positive who actually have disease (true positive) / number of positive tests
If cutoff value is too low, what happens to sensitivity? - ✔✔Everything above cutoff is
considered true positive, so sensitivity would go up
Disclaimer: Original Content, No Copyright Infringement, All Rights Reserved © 2025 4
