"The Providence Fire Department conducted a staffing study in 1990-1991 to determine the effect of increased staffing on injury-related costs. Staffing on the six busiest companies was increased from three members to four. An actuary concluded that a substantial savings was achieved, resulting in permanent staffing increases. The results of the staffing study were subject to criticism on the basis of participant bias and the Hawthorne Effect, because participating firefighters knew of the study, and of the possibility for permanent staffing increases. The problem prompting this research was that increased staffing remained highly controversial due to budgetary problems facing Providence. Politicians and the media regularly referred to the department as 'bloated.' The purpose of this research was to determine if injury reductions observed during the original staffing study continued during subsequent years. The historical method was used."
National Fire Academy: https://nfa.usfa.fema.gov/