Evaluation studies without a concurrent control group
were also systematically searched, as well as case-reference
and retrospective studies, in order to gain some degree
of perspective from lower-quality studies that would
otherwise be excluded from the review because of lack
of rigor or nonstandard study design. Five before–after
studies12,33,35–37 without a concurrent control group
and one retrospective study34 with measurements before
and after the intervention were found. Among
these studies was an additional one on legislation34 and
two on drug testing to prevent nonfatal injuries.33,35 In
addition, there were two studies12,36 that evaluated the
effect of education and training on preventing nonfatal
injuries. Finally, there was one study37 that evaluated an
organizational intervention (i.e., a company-wide 5-step
health and safety plan) on nonfatal injuries, but it was
impossible to extract the outcomes, and the authors