Table 1. Criteria for the Quality of the Study Design
Data for each journal are the percent of trials for which the criterion was present during the periods 1981–1985 ⇒ 1991–1995 ⇒ 2000.
* Based on pooled scores from the four journals for each criterion between 1981–1985 and 1991–1995 only.
†P < 0.0083, 1991–1995 value compared with 1981–1985 value for the same journal.