The assessment identified 136 schools with playground equipment
that represented a severe hazard (i.e., an imminent risk of
serious and permanent injury, usually indicating risk of a fall
from more than 1.5 m or a fall onto unsuitable surfacing), did not
meet CSA standards and was impractical to retrofit to make safer
(Fig. 1). The equipment was removed from all 136 schools in the
summer of 2000. By Dec. 31, 2001, the equipment had been fully
replaced in 86 schools, which constituted the intervention group;
it had not been fully replaced in the remaining 50 schools, and
they were excluded from analysis (Fig. 2). Injury rates before and
after equipment replacement were compared in the intervention
schools. A total of 225 schools had equipment that did not require
replacement, and they constituted the nonintervention
schools; injury rates in this group served as an indicator of stability
of baseline injury rates in this natural experiment. A total of
34 557 students attended the intervention schools, and 88 417 attended
the nonintervention schools. All schools included grades
1 through 6 and were public schools.