“…A number of investigators used quantitative measures to assess change; for example, injury rates, 15,23 airborne concentrations, 16 biomarkers, 13,21 work practices, 14,20,23 and program elements. 20 Others employed self-reports of symptoms 4 or knowledge, attitudes, and work practices. 12,[17][18][19] We are greatly encouraged by the number and variety of articles included in this supplement.…”