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Table 1 Anchor-based calculations of MID for the VAS and the FHSQ

From: Minimal Important Difference (MID) of two commonly used outcome measures for foot problems

Outcome Domain 0 to +1 +2 to +3 MID values 95% CI
Measure   n = 57 n = 40   
VAS Average -1.1§ -8.9 -7.8 -11.7 to -3.9
  1st Step -1.9 -20.5 -18.6 -24.6 to -12.6
FHSQ Pain 8.7 21.2 12.5 5.8 to 19.2
  Function 4.8 11.9 7.1 0.7 to 13.4
  Footwear 1.9 -0.2 -2.1 -8.0 to 3.8
  GFH 8.3 7.9 -0.4 -7.1 to 6.4
  1. Abbreviations: VAS = Visual Analogue Scale, FHSQ = Foot Health Status Questionnaire, MID = Minimal Important Difference, GFH = General Foot Health, CI = Confidence Interval.
  2. Note: Three variables were initially not normally distributed, so outliers that were 3SDs from the mean were removed to ensure normalcy. Accordingly, some variables had a lower sample size due to this, which the following symbols represent: §n = 55, n = 56, n = 39.