Table 2. Characteristics and return-of-results practices of index studies.

	Number (Percent)
Nature of data acquisition
Primary data/specimen collection	126 (63%)
Secondary data/specimen analysis	74 (37%)
	Primary Collection	Secondary Use
Mode of acquisition of data or specimens*	NA
From those responsible for primary data collection		57 (77%)
From a public repository		5 (7%)
Other		12 (16%)
Signed data use agreement†	NA
Yes		49 (67%)
No		14 (19%)
Unsure		10 (14%)
If present, data use agreement forbade participant re-identification‡	NA
Yes		29 (60%)
No		9 (19%)
Unsure		10 (21%)
Method to link data/specimens to individual identifiers§
Directly labeled with identifiers	3 (2%)	0 (0%)
Linked to identifiers with code	109 (87%)	30 (67%)
No link to identifiers	9 (7%)	12 (27%)
Other	3 (2%)	3 (7%)
Unsure	2 (2%)	0 (0%)
Study has previously returned individual genetic test results to participant(s)**
Yes	7 (6%)	0 (0%)
No	107 (91%)	32 (97%)
Unsure	3 (3%)	1 (3%)
Study has plans to return individual genetic test results to participant(s) ††,‡‡
Yes	2 (2%)	0 (0%)
No	103 (94%)	33 (100%)
Unsure	5 (5%)	0 (0%)

NA, Not applicable

^*Secondary analysis, n=74

^†Secondary analysis, n=73

^‡Secondary analysis, n=48

^§Primary analysis, n=126; secondary analysis, n=45

^**Primary analysis, n=117, secondary analysis, n=33

^††Primary analysis, n=110, secondary analysis, n=33

^‡‡Among studies that had not previously returned results to individual participants