Research design and statistical methods in Chinese medical journals.

CONTEXT Study design and statistical analyses have improved in journals published in Western countries, but the type of research designs and statistical methods used in medical journals outside Western countries has not been assessed. OBJECTIVES To determine the frequency of research designs and statistical techniques used in Chinese medical journals, types of statistical errors present, and trends over a 10-year period. DESIGN Evaluation of all original articles published in 5 leading journals in 1985 (N = 640) and in 1995 (N = 954). MAIN OUTCOME MEASURES Research designs and statistical methods. RESULTS Compared with 1985, significant improvement was seen in 1995; the percentages of original articles reporting clinical trials, prospective studies, or basic science research increased from 18% to 31% (P<.001), the proportion of papers using statistical tests increased from 40% to 60% (P<.001), more sophisticated statistical methods were used, and of those articles using statistics, the proportion using appropriate methods increased from 22% to 46% (P<.001). In both years, the most commonly used statistical methods were t tests and contingency tables. The most common errors were presentation of P values without specifying the test used, use of multiple t tests instead of analysis of variance, and use of unpaired t tests when paired tests were required. CONCLUSIONS The use of statistical methods in Chinese medical journals research is improving, and by 1995, the frequency of using statistical methods in published articles was similar to the results determined in previous studies of journals. However, the lack of or inappropriate use of statistics remains a serious problem.