A general procedure for establishing composite quality evaluation indices based on key quality attributes of traditional Chinese medicine

•Licorice roots are widely used in traditional Chinese medicine (TCM).•Quality attributesinTCMinclude growth years, location, and harvest season.•11 licorice compounds are related tokey quality attributes of TCM formulations.•Liquiritin and 8 other compoundsare quality evaluation indices of licorice.•TCM composite quality evaluation indices will be used for quality control.