ABFM EPIDEMIOLOGY TEST QUESTIONS AND
ANSWERS
What is Relative Risk? - ANSWER 1. The ratio of outcome occurrence in
exposed versus unexposed.
2. The experimental event rate (exposed) divided by the control event rate (not
exposed).
Equation 1: Relative Risk (RR) = EER divided by CER.
Relavative Risk Reduction To calculate RRR, divide CER - EER by CER.
Equation 2: Absolute risk reduction: ARR - ANSWER = CER - EER
Equation 3: To calculate the number of treatments needed, divide NNT by ARR
(NNT=1/ARR).
Equation 4: Sensitivity - Answer True Positives are the percentage of people
who can be identified as having the disease.
Use in screening to rule out illness.
ELISA for H I V - we don't want to miss anyone.
To calculate sensitivity, divide true positives (TP) by (TP + FN) and multiply by
100.
Sensitivity is the ability to detect people with disease.
SNOUT - ANSWER SeNsitive tests with negative results rule out the disease.
Specificity - Answer Ability to identify individuals who do not have the
disease. Used to confirm the result.
Western Blot for HIV is a good example.
ANSWERS
What is Relative Risk? - ANSWER 1. The ratio of outcome occurrence in
exposed versus unexposed.
2. The experimental event rate (exposed) divided by the control event rate (not
exposed).
Equation 1: Relative Risk (RR) = EER divided by CER.
Relavative Risk Reduction To calculate RRR, divide CER - EER by CER.
Equation 2: Absolute risk reduction: ARR - ANSWER = CER - EER
Equation 3: To calculate the number of treatments needed, divide NNT by ARR
(NNT=1/ARR).
Equation 4: Sensitivity - Answer True Positives are the percentage of people
who can be identified as having the disease.
Use in screening to rule out illness.
ELISA for H I V - we don't want to miss anyone.
To calculate sensitivity, divide true positives (TP) by (TP + FN) and multiply by
100.
Sensitivity is the ability to detect people with disease.
SNOUT - ANSWER SeNsitive tests with negative results rule out the disease.
Specificity - Answer Ability to identify individuals who do not have the
disease. Used to confirm the result.
Western Blot for HIV is a good example.
