Table 2

Distribution of floor surface roughness (Ra and Rpm), coefficient of friction, floor cleaning frequency, use of slip-resistant shoes, rate of slipping and rate of major slipping

Restaurant-level variables (n=36)
Mean Ra (μm)*
 Mean (SD)3.7 (1.1)
 Median (range)3.2 (2.2 to 6.1)
Mean Rpm (μm)*
 Mean (SD)14.4 (4.4)
 Median (range)12.8 (8.2 to 26.2)
Mean coefficient of friction (0 to 1)†
 Mean (SD)0.67 (0.08)
 Median (range)0.68 (0.45 to 0.86)
Floor-cleaning frequency/day (n, %)
 17 (19.4)
 211 (30.6)
 36 (16.7)
 47 (19.4)
 52 (5.6)
 6+3 (8.3)
Individual-level variables (n=422)
Slip-resistant shoe (n, %)286 (67.8)
Rate of slipping per 40 work hours
 Mean (SD)0.69 (1.77)
 Median (range)0.14 (0.00 to 22.22)
Rate of major slips‡ per 40 work hours
 Mean (SD)0.052 (0.25)
 Median (range)0.00 (0.00 to 3.73)

  • ↵* n=35 as floor surface roughness could not be measured in one of the restaurants.

  • ↵† Coefficient of friction is a unitless number with values ranging from 0 to 1.

  • ↵‡ A major slip was defined as a slip that resulted either in a fall or in an injury.