Was the Study Big Enough?

All too often, studies evaluating diagnostic tests are too small.

Deciding how big a diagnostic study needs to be before you start is complicated. Deciding whether a study is big enough after it has been done is straightforward.

The best way to judge is to look at the width of the confidence intervals, as this reflects how much uncertainty there is around the value.

Narrow confidence intervals mean that the estimate is precise, and this trial has narrow confidence intervals reported in the text.