Stern 1997.

Methods	Studies submitted and approved by the ethics committee of the Royal Alfred Hospital Sydney between 1979 and 1988. Publication status was obtained in July 1992 by a telephone call to the principal investigator of each study.
Data	130 completed trials.
Comparisons	Publication status of trials with significant findings compared with those with non‐significant or null findings. Trials were classified as either significant if P < 0.05, as showing a non‐significant trend if the difference had a P between 0.05 and 0.10, or as null if no difference was observed between the two groups.
Outcomes	Trials with significant findings were more likely to be published than those showing null findings. Total published = 73/130 (56%) Significant = 55/76 (72%) Non significant trend = 3/15 (20%) Null = 15/39 (38%) Other variables assessed included time to publication, funding and sample size.
Notes	748 studies were included by the ethics committee of which 130 were included in the analysis. Reasons for exclusion were: no response from investigators (n = 228); analysis not yet begun (n = 199); qualitative studies (n = 103); not clinical trials (n = 88).
Risk of bias
Item	Authors' judgement	Description
Inception cohort?	Yes	"Eligible studies were defined as single studies approved by the Royal Prince Alfred Hospital Ethics Committee between September 1979 and December 1988 with more than one patient and with protocol information available." (page 642)
Complete follow up of all trials?	No	748 studies were included by the ethics committee of which 130 were included in the analysis. Reasons for exclusion were: no response from investigators (n = 228); analysis not yet begun (n = 199); qualitative studies (n = 103); not clinical trials (n = 88). There was 70% of follow up.
Publication ascertained through personal contact with investigators or sponsor?	Yes	"In July 1992 the principal investigator for each study was asked to complete a questionnaire providing information on the current status; starting date, closure of recruitment, and finishing date; sample size reached; the nature of funding (none, pharmaceutical, government, other (external), or other (internal)); the rating of scientific importance of the study; the status and date of the most recent analysis; the main research questions posed by the study at the outset; the results for the main research questions; and the publication status and date of initial publication as an article in a peer reviewed journal." (page 642)
Definition of positive and negative findings clearly defined?	Yes	"For quantitative studies, in which the main study outcome was assessed by using statistical methods with tests of significance, outcome was classed as significant (P < 0.05), as showing a non‐significant trend (0.05 < P < 0.10), or as non‐significant or null (P > 0.10) ... For qualitative studies, in which the main study outcome was assessed subjectively by the principal investigator, the study was classed as showing striking, important and definite, or unimportant and negative findings." (page 642)
Possible confounders controlled for in the analysis?	Yes	"With the exception of the investigator's rating of scientific importance of the study, which we judged to be largely influenced by study results, all other factors were examined in a multivariate Cox regression to determine the relative importance of study results on time to publication adjusted for any other significant factors." (page 642)