Module 5

Question 1

Sensitivity

Answer 1

number of true positives/number of true positives + number of false negatives

The ability of a test to correctly identify those with the disease

Question 2

Specificity

Answer 2

Number of true negatives/number of true negatives+ number of false positives

The specificity of a test is its ability to identify the people who do not have the disease

Question 3

Positive Predictive Value (PPV)

Answer 3

Number of true positives/number of true positives + the number of false positives.

What proportion of those who test positive actually have the disease

Question 4

Negative Predictive Value (NPV)

Answer 4

Number of true negatives/number of true negatives + number of false negatives

If a patient tests negative, what is the probability that this patient doesn’t have the disease

Question 5

Sequential Testing

Answer 5

A person must receive a positive screen on post tests to be classifies as having the health outcome. This results in a loss in sensitivity but a gain in specificity

Question 6

Simultaneous Testing

Answer 6

A person must receive a negative screen on both tests to be classified as not having the health outcome. This results in a gain in sensitivity but a loss in specificity.