BHS Epidemiology 5

Question 1

The secondary attack rate (SAR) in a household outbreak measures:

Accepted Answer

New cases among susceptible contacts exposed to a primary case

Answer

SAR is the proportion of susceptible household contacts who develop disease after exposure to a primary case, reflecting household transmissibility.

Question 2

When does the positive predictive value (PPV) of a test increase, assuming fixed sensitivity and specificity?

Accepted Answer

When disease prevalence increases

Answer

PPV rises with higher disease prevalence because a greater proportion of positive tests will be true positives in a more affected population.

Question 3

An investigator is studying whether air pollution exposure differs between asthma cases and healthy controls. The primary concern with retrospective exposure assessment is:

Accepted Answer

Differential recall of exposure

Answer

Retrospective assessment risks differential recall because cases may remember or report exposures differently than controls.

Question 4

The population attributable risk percent (PAR%) quantifies:

Accepted Answer

The proportion of disease in the total population attributable to the exposure

Answer

PAR% estimates what fraction of the total disease burden could theoretically be prevented if the exposure were eliminated from the population.

Question 5

A randomized trial is described as double-blind. This means:

Accepted Answer

Neither the participants nor the outcome assessors know the treatment assignment

Answer

Double-blinding means participants cannot change behavior based on treatment knowledge and assessors cannot introduce measurement bias.

BHS - Bachelor of Health Science Practice Test

BHS - Bachelor of Health Science Practice Test

BHS Epidemiology 5