Question

which of the following scenarios describes a trade - off between sensitivity and specificity?
increasing the threshold for a positive test to catch more cases reduces false negatives but increases false positives.
lowering the threshold for a positive test increases false negatives but reduces false positives.
increasing sensitivity also increases specificity.
a test with high sensitivity will always have high specificity.

Explanation:

Sensitivity is the ability of a test to correctly identify those with the disease (true - positives), and false - negatives are cases where the test wrongly identifies a diseased person as non - diseased. Lowering the threshold for a positive test means more people are classified as positive. This would reduce false - negatives (as more of the actually diseased are caught) but increase false - positives (more non - diseased are wrongly classified as positive). The other options are incorrect:

• Option 2: Lowering the threshold for a positive test reduces false - negatives (not increases) and increases false - positives (not reduces).
• Option 3: There is usually a trade - off, so increasing sensitivity does not increase specificity.
• Option 4: A test with high sensitivity does not always have high specificity due to the trade - off relationship.

Answer:

Increasing the threshold for a positive test to catch more cases reduces false negatives but increases false positives.