THE EVALUATION OF THE USE OF STATISTICAL TECHNIQUES IN ORIGINAL ARTICLES PUBLISHED IN MEDICINA-CLINICA OVER 3 DECADES (1962-1992)

BACKGROUND: The incorrect use of statistical techniques in medical art icles may seriously compromise the validity of conclusions. This findi ng otherwise is relatively common. METHODS: A total of 84 original art icles published in MEDICINA CLINICA between 1962 and 1992 were reviewe d with the aim of assessing the use and appropriateness of statistical techniques. The use of statistics, the quality of the analyses perfor med, and the inaccuracy of the statistical techniques used were evalua ted. We also classified the statistical techniques most commonly used throughout the study period. RESULTS: There was a marked increase in t he use of statistical analyses, from 8.3% in 1962 to 83.3% in 1992. It should be noted that a substantial part of this increase has been due to the use of inferential tests, which accounted up to 70% in the sam ple of articles published in 1992. This finding, however, was associat ed with an increase in the number of incorrect analyses. The most comm on statistical errors included assumption of normal distribution of da ta (with no mention of the test used to confirm this fact), mistake be tween standard deviation and standard error of the mean, inadequate in ferences on the basis of the sample size, inappropriate use of the Stu dent's t test, chi-square test, nonparametric tests or multivariate an alyses as well as misunderstanding of linear regression and correlatio n. CONCLUSIONS: High standards in scientific research have been accomp anied by a significant increase in the number of clinical studies with statistical analysis of data. However, this apparently favorable situ ation has been associated with an increase in the number of inaccurate analyses. It has been found that sophisticated statistical tests are rarely used in articles published in MEDICINA CLINICA.