Since 2006, the CORESTA Cigar Smoking Methods Sub-Group conducts periodic collaborative studies in order to improve repeatability and reproducibility measurement methods of different cigar sizes and types.

The purpose of the 16^th Collaborative Study is to estimate the mean values, repeatability, and reproducibility for NFDPM (tar), nicotine, carbon monoxide and other measures for different sizes and types of cigar products and test pieces and to provide a tool for participating laboratories to prove competence in cigar smoke analysis. 

Most of the mean values were in reasonable agreement with the 2020 results. The r & R results indicated large variability, but this is in line with the inherent variability seen with cigars. The z-scores indicated reasonable agreement among the laboratories, except for a few that exceeded |z|>3 and warrant investigation by the corresponding laboratory.