OBJECTIVE - This study describes the development of a preliminary version of an instrument that attempts to assess the quality of reports of individualized homeopathic prescriptions in clinical trials and observational studies.METHODS - A multidisciplinary panel of 15 judges produced an initial version of the instrument through iterative Delphi rounds and pilot-tested the instrument on five clinical trials. Later they assessed, under blind conditions, the individualization quality of 40 randomly-selected research reports. The final version of the instrument included six criteria. These items were scored consistently by all the raters regardless of background.RESULTS - The instrument appeared to have adequate face and content validity, acceptable internal consistency or reliability (Cronbach's α 0.606 - 0.725), significant discriminant validity (F = 398.7; P < 0.000 1), moderate interrater reliability (Fleiss κ 0.533), agreeable test-retest reliability (Cohen's κ 0.765 - 0.934), moderate sensitivity (0.4; 95% confidence interval 0.253-0.566), and high specificity (1.0; 95% confidence interval 0.891-1.000).CONCLUSION - The initial data suggest that this instrument may be a promising systematic tool amendable for further development.