Changes in statistical practices and reporting have been documented by Giofrè et al. PLOS ONE 12(4), e0175583 (2017), who investigated ten statistical and open practices in two high-ranking journals (Psychological Science [PS] and Journal of Experimental Psychology-General [JEPG]): null hypothesis significance testing; confidence or credible intervals; meta-analysis of the results of multiple experiments; confidence interval interpretation; effect size interpretation; sample size determination; data exclusion; data availability; materials availability; and preregistered design and analysis plan. The investigation was based on an analysis of all papers published in these journals between 2013 and 2015. The aim of the present study was to follow up changes in both PS and JEPG in subsequent years, from 2016 to 2020, adding code availability as a further open practice. We found improvement in most practices, with some exceptions (i.e., confidence interval interpretation and meta-analysis). Despite these positive changes, our results indicate a need for further improvements in statistical practices and adoption of open practices.

OBJECTIVE: To examine whether appropriate statistical methods were used in acupuncture randomized controlled trials (RCTs).
METHODS: We searched PubMed to identify acupuncture RCTs with continuous outcome as primary outcome published in the core clinical journals and complementary and alternative medicine (CAM) journals between January 2010 and December 2019 (10 years). We compared statistical characteristics of included trials published in core clinical journals and CAM journals.
RESULTS: We included 262 RCTs, including 46 published in core clinical journals and 216 in CAM journals. Of included RCTs, only 132 (50.4%) clearly predefined the primary outcome, 72 (27.5%) specified the use of intention to treat or modified intention to treat population for primary analysis. In the 167 trials reported missing participant data (MPD), 118 (70.7%) used suboptimal methods (e.g., complete case analysis) for dealing with MPD; 11 (6.6%) conducted sensitivity analysis regarding MPD. Among the 161 trials with repeated measures design, only 21 (13.0%) used advanced statistical models (e.g., mixed-effects models) for handling repeated-measure data in the primary analysis. In the 72 trials involving multiple acupuncturists, only 4 (5.6%) adjusted acupuncturist variable or considered the clustering by acupuncturist in analysis. Trials in core clinical journals were more likely to predefine primary outcome (78.3% vs. 44.4%, P < 0.001), use multiple imputations for handling MPD (40% vs. 1.5%, P < 0.001), and use statistically advanced methods for assessing treatment effect at a single time point (26.1% vs. 2%, P = 0.001).
CONCLUSIONS: The use of statistical methods among acupuncture RCTs is far from satisfactory. Our findings highlighted the need for researchers to carefully use the optimal statistical methods and for journal editors to strengthen the use of statistical methods.