Table 4. Aspects of study level publication bias.
| Study | Definition of published article employed by eligible studies | Time since protocol approved | % Not submitted1 (95% CI) | % Submitted but not accepted2 (95% CI) | % Studies not published that were not submitted (95% CI) |
| Easterbrook, 1991 [24] | Acceptance by a journal (published or in press), but not book chapters or published meeting abstracts or proceedings. | 3 years | 9 (6, 12) | 6 (3, 9) | 63 (49, 77) |
| Dickersin, 1992 [23] | Reported in one or more journal articles, monographs, books, or chapters in books, were available from medical libraries or were in documents available from a published archive, e.g., the National Technical Information service | 8 years | 23 (19, 27) | 1.5 (0, 3) | 95 (91, 99) |
| Dickersin, 1993 [3] | Abstracts, journal articles, book chapters, proceedings, letter to the editor, or other material. | 9 years | 7 (3, 11) | 0 | 100 |
| Stern, 19973 [4] | As an article in a peer reviewed journal | 4 plus years | 33 (28, 38) | 13 (8,17) | 80 (73, 87) |
| Cooper, 1997 [19] | NI | NI | NI | ||
| Wormald, 1997 [30] | NI | 2 to 34 years | 21 (8,34) | 0 | 100 |
| Ioannidis, 1998 [5] | Peer-reviewed journal articles | 12% completed less than 1 year ago, 20% completed over 1 year ago. | 32 (21, 43) | 20 (8, 32) | 70 (54, 86) |
| Pich, 2003 [27] | Peer reviewed journal articles | 3 years | * | ||
| Cronin, 2004 [20] | NI | 1 to 5 years | * | ||
| Decullier, 20053 [7] | Published as a scientific paper. Grey literature – published in other formats than scientific papers, that is generally not accessible through libraries (internal reports, theses, abstracts, posters) | 6 years (2% not ready) | 58 (54,62) | 2 (0, 4) | 99 (98, 100) |
| Decullier, 20063 [22] | Published as a scientific paper | 6 years | 47 (37,57) | 2 (0, 6) | 98 (95, 100) |
| Hahn, 2002 [26] | Published article or a written study report | 5 years | * | ||
| Chan, 2004a3 [18] | Journal article | 4 years | 31 (22,40) | 1 (0, 3) | 97 (91, 100) |
| Chan, 2004b3 [17] | Journal article | 8 years | 56 (50, 62) | 2 (0, 5) | 99 (97, 100) |
| Ghersi, 2006 [25] | NI | NI | NI | ||
| Von Elm, 2008 [29] | Journal article | 8 years | * | ||
| Turer 2007 [28] | Peer reviewed journal articles | 7 years | 26 (20,33)4 | * | * |
| De jong 2010 [21] | An original article containing study results, indexed in MEDLINE, EMBASE, PsychINFO, or the Cochrane Library | 6 months to 9 years | NI | ||
| Blumle 2008 [31] | Articles published in scientific journals that provide adequate information on at least the objectives of the study as well as on its methods and results | 7 years | * | ||
| Hall 2007 [32] | Peer reviewed journal | 10–11 years | NI | ||
1
Denominator is the total number of studies with known publication status in the cohort i.e. published plus unpublished plus in preparation plus in press.
2
Denominator is the number submitted.
3
Denominator includes ongoing studies.
4
This is the number never presented and we have assumed not submitted.
*
Question not asked. NI No information available.