Introduction: It is well recognised that a register of randomised trials would be incomplete if it relied solely on trials identified by current electronic searching methods.
Objective: To identify all randomised trials published in the New Zealand Medical Journal, to document the basic characteristics of these trials and to count the number that were detectable on Medline.
Methods: All issues of the New Zealand Medical Journal between 1943 and 1995 were systematically hand-searched and identified trials were characterised. The proportion of these trials detectable by a maximally sensitive Medline (1995 release) search strategy was calculated.
Results: The hand search identified 152 randomised controlled trials. Only 18% of studies reported on the method of randomisation and only 13% provided evidence that final analyses were conducted on an intention to treat basis. Since 1966, when Medline became available, 143 trials were published of which 89 (62%) were identified by the Medline search.
Discussion: Important information on design and analysis was frequently absent from the trial reports. In addition over one third of randomised trials were not identified by the optimal Medline search strategy. These findings are consistent with previous studies.