“…According to multiple contributions to this special issue, test results do not match purchase intent for approximately 12%–17% of tested substances of concern (Barratt et al , 2022; Díaz Moreno et al , 2022; Kaskela et al , 2022; Kushakov et al , 2022; Measham and Simmons, 2022; Valente et al , 2022). When tested substances of concern do not match expectations, a robust and growing body of research (Measham, 2019; Valente et al , 2019; for a review, see Giulini et al , 2022; Maghsoudi et al , 2021) finds that service users discard these substances. This finding was replicated in two contributions to this special issue with comparable methods (Barratt et al , 2022; Measham and Simmons, 2022).…”