Yin scores and Yang scores:: A new method for quantitative diagnostic evaluation in traditional chinese medicine research

Objective: To develop and evaluate a method for quantitative evaluation of yin and yang (yin and yang scores) in human subjects for the purposes of research. This method aims to classify subjects into groups allowing future quantitative testing of key research questions such as: do different groups of patients respond differently to acupuncture treatments or Chinese herb formulas? Methods: In a pilot study of inter-rater reliability, 12 volunteers were each successively interviewed and examined by 6 acupuncturists on the same day. Each acupuncturist gave each volunteer a score for yin and a score for yang on a scale of -10 to +10, zero representing a "balanced" score. Acupuncturists were blinded to each other's scores. Results: Overall mean (+/-standard deviation [SD]) yin and yang scores were -1.86 +/- 0.90 and -0.68 +/- 1.23 respectively. Intraclass correlations (ICCs) associated with a single acupuncturist's ratings were 0.35 (yin) and 0.36 (yang). ICC's for subject's mean scores based on the six acupuncturists were 0.77 (yin) and 0.78 (yang). Significant differences in mean scores across subjects were detected for yin (p < 0.001) and yang (p < 0.001) (repeated-measures analysis of variance [ANOVA]) based on the multiple acupuncturists' ratings. Conclusion: These results indicate that (1) yin and yang can be quantified in a reliable manner, but evaluation by multiple acupuncturists is necessary to obtain a reliable score; (2) yin and yang scores can be used to group individuals for the purposes of statistical analysis. Further evaluation of yin and yang scores in a greater number and wider variety of patients will be needed to evaluate the potential usefulness of this measurement tool in acupuncture clinical trials and basic physiologic research.