CPH Exam Study Guide –
Practice Questions with
Verified Answers. GRADED A+.
Latest 2026/2027 Update
Attributable risk - Answer✔✔-Rate of disease in exposed individuals that can
be attributed to the exposure. Or the proportion of all cases that can be
attributed to a particular exposure.
Adjusted rate - Answer✔✔-Effects of differences in composition of pops being
compared have been minimized by statistical methods.
ex: regression analysis and strandardization
-often used on rates or relative risks
Ecological Fallacy - Answer✔✔-Bias that may occur because an association
observed between variables or an aggregate level does not represent the
association that exists at an individual level
Confidence Interval - Answer✔✔-95% confident that the true value of a
variable is contained within the interval.
-used to account for sampling variability
,-it is a point estimate +_ margin of error, where the point estimate is the best
estimate of teh unknown parameter and the margin of error is the product of
the confidence level and the standard error.
if a 95% CI for the differences in mean does not include 0 (the null value) then
there is eveidence of a statistically significant difference at sigma=0.05
Clinical Trial Phases - Answer✔✔-1. Safety and Pharmacologic profiles
2. pilot efficacy studies
3. extensive clinical trials
4. after the FDA approves, look at specific effects to establish incidence of
adverse reactions, etc. longterm use effects.
interpretation of studies - Answer✔✔-temporality: cause precedes effect
Specificity: important in assessing the possibility of biases.
Consistency: several studies showing similar results. homogeneity statistically.
Confounders - Answer✔✔--non-causal association between exposure and
outcome as a result of a third variable.
-distortion of effect by other factors
-must be related to exposure AND outcome
-not an intermediate variable on causal pathway
Controlling for confounders - Answer✔✔-before data collection: random
collection, individual matching, frequency matching
After data collection: direct adjustment, indirect adjustment, mantel-haenszel,
regression techniques
,Quality Assurance vs. Quality Control - Answer✔✔-QA: ensure quality before
data collection
QC: monitor and maintain quality during study
reliability vs. validity - Answer✔✔-R: precision, reproducibility
V: accuracy, absence of bias
systematic error - Answer✔✔-(lack of validity) if there's a difference between
what is actually being estimated and what is intended to be measured.
Increasing sample size doesn't help.
Random Error - Answer✔✔-(lack of precision) occurs, but increasing sample
size helps.
RCT studies - Answer✔✔-Tests efficacy or effectiveness of healthcare services.
random allocation of participants to different treatments. Includes blinding,
placebo. gold standard for evidence.
Community Intervention/cluster RCT - Answer✔✔-community-wide basis or
groupwide
Case-Crossover RCT design - Answer✔✔--cases serve as their own control
-exposure has transient effect
Cross Sectional Studies - Answer✔✔-SNAPSHOT! at a single point in time. tells
the prevalence and association. causation cannot be implied. a study that
, examines the relationship between diseases and other variables as they exist in
a defined population at one particular time.
Matching - Answer✔✔-used to make cases and controls as similar as possible
to avoid confounding. ex: race, gender, age. +Maybe the only way to control
confounding. increases statistical power, straightforward. -requires use of
special analytical techniques, residual confounding can occur if you match
continuous variables by category.
types of matching - Answer✔✔-individual matching: case and control matched
individually
frequency matching: a group of controls
Minimum Euclidean Distance measure: match to closest person.
Cohort Studies - Answer✔✔-RISK RATIO, RELATIVE RISK, INCIDENCE RATE, RATE
RATIO
-rare exposures
-group of subjects who shared experiences during a particular time.
Determines if incidence is related to exposure.
Concurrent/longitudinal cohort studies - Answer✔✔-starts now (with a
baseline exam) and goes into future. expensive and time intensive.
non-concurrent/retrospective cohort studies - Answer✔✔-assembled in past
based on existing records. faster and quicker, but records can be limited or
biased. follow up can be hard.
Practice Questions with
Verified Answers. GRADED A+.
Latest 2026/2027 Update
Attributable risk - Answer✔✔-Rate of disease in exposed individuals that can
be attributed to the exposure. Or the proportion of all cases that can be
attributed to a particular exposure.
Adjusted rate - Answer✔✔-Effects of differences in composition of pops being
compared have been minimized by statistical methods.
ex: regression analysis and strandardization
-often used on rates or relative risks
Ecological Fallacy - Answer✔✔-Bias that may occur because an association
observed between variables or an aggregate level does not represent the
association that exists at an individual level
Confidence Interval - Answer✔✔-95% confident that the true value of a
variable is contained within the interval.
-used to account for sampling variability
,-it is a point estimate +_ margin of error, where the point estimate is the best
estimate of teh unknown parameter and the margin of error is the product of
the confidence level and the standard error.
if a 95% CI for the differences in mean does not include 0 (the null value) then
there is eveidence of a statistically significant difference at sigma=0.05
Clinical Trial Phases - Answer✔✔-1. Safety and Pharmacologic profiles
2. pilot efficacy studies
3. extensive clinical trials
4. after the FDA approves, look at specific effects to establish incidence of
adverse reactions, etc. longterm use effects.
interpretation of studies - Answer✔✔-temporality: cause precedes effect
Specificity: important in assessing the possibility of biases.
Consistency: several studies showing similar results. homogeneity statistically.
Confounders - Answer✔✔--non-causal association between exposure and
outcome as a result of a third variable.
-distortion of effect by other factors
-must be related to exposure AND outcome
-not an intermediate variable on causal pathway
Controlling for confounders - Answer✔✔-before data collection: random
collection, individual matching, frequency matching
After data collection: direct adjustment, indirect adjustment, mantel-haenszel,
regression techniques
,Quality Assurance vs. Quality Control - Answer✔✔-QA: ensure quality before
data collection
QC: monitor and maintain quality during study
reliability vs. validity - Answer✔✔-R: precision, reproducibility
V: accuracy, absence of bias
systematic error - Answer✔✔-(lack of validity) if there's a difference between
what is actually being estimated and what is intended to be measured.
Increasing sample size doesn't help.
Random Error - Answer✔✔-(lack of precision) occurs, but increasing sample
size helps.
RCT studies - Answer✔✔-Tests efficacy or effectiveness of healthcare services.
random allocation of participants to different treatments. Includes blinding,
placebo. gold standard for evidence.
Community Intervention/cluster RCT - Answer✔✔-community-wide basis or
groupwide
Case-Crossover RCT design - Answer✔✔--cases serve as their own control
-exposure has transient effect
Cross Sectional Studies - Answer✔✔-SNAPSHOT! at a single point in time. tells
the prevalence and association. causation cannot be implied. a study that
, examines the relationship between diseases and other variables as they exist in
a defined population at one particular time.
Matching - Answer✔✔-used to make cases and controls as similar as possible
to avoid confounding. ex: race, gender, age. +Maybe the only way to control
confounding. increases statistical power, straightforward. -requires use of
special analytical techniques, residual confounding can occur if you match
continuous variables by category.
types of matching - Answer✔✔-individual matching: case and control matched
individually
frequency matching: a group of controls
Minimum Euclidean Distance measure: match to closest person.
Cohort Studies - Answer✔✔-RISK RATIO, RELATIVE RISK, INCIDENCE RATE, RATE
RATIO
-rare exposures
-group of subjects who shared experiences during a particular time.
Determines if incidence is related to exposure.
Concurrent/longitudinal cohort studies - Answer✔✔-starts now (with a
baseline exam) and goes into future. expensive and time intensive.
non-concurrent/retrospective cohort studies - Answer✔✔-assembled in past
based on existing records. faster and quicker, but records can be limited or
biased. follow up can be hard.
