In order to establish the best statistical procedure for estimating improved compositional data in geochemical reference materials for quality control purposes, we evaluated the test performance criterion (πD|C) and swamping (πswamp) and masking (πmask) effects of 30 conventional and 32 new discordancy tests for normal distributions from central tendency slippage δ = 2–10, number of contaminants E = 1–4, and sample sizes n = 10, 20, 30, 40, 60, and 80. | Improved composition of Hawaiian basalt BHVO-1 from the application of two new and three conventional recursive discordancy tests