Table 1.

Contingency tables showing the summary totals in each of the cells after pooling all the junior doctors

Pooled data for the junior doctors
	High-prevalence population (77%)			Low-prevalence population (13%)
	Reference standard			Reference standard
	Positive	Negative		Positive	Negative
Doctor's diagnosis
Positive	159	22	181	72	50	122
Negative	10	28	38	24	602	626
Totals	169	50	219	96	652	748

Note x-rays in the high/low-prevalence population were those interpreted by the radiographer as having a high/low probability of an abnormal feature. The true prevalence is determined by the reference standard.