Table 1.

Possible data outcomes and probabilities for study i (i=1, . . ., m). In each cell, the first row shows the observed count, the second row shows the corresponding conditional probability of test outcome given disease status in case-control studies, or the corresponding probability of cell memberships in cohort studies.

	Disease Status by a Gold Standard Test (D)
Diagnostic test (T)	1a. Case-control studies (i=1, 2, . . ., m1)		1b. Cohort studies (i=m1+1, m1+2, . . ., m)
	Disease (+)	Non-disease (−)	Disease (+)	Non-disease (−)
Positive (T+)	ni11 Sei	ni10 1 – Spi	ni11 πiSei	ni10 (1 – πi) (1 – Spi)
Negative (T−)	ni01 1 – Sei	ni00 Spi	ni01 πi (1 – Sei)	ni00 (1 – πi)Spi
Total	ni1 1	ni0 1	n i1 π i	ni0 1 – πi