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Table 4 Psychometric comparison of the original and short FES-I, n = 101

From: Psychometric properties of the original and short versions of the Falls Efficacy Scale-International (FES-I) in people with Parkinson’s disease

  Original FES-I Short FES-I
Missing item responses 0.9% 0.7%
Corrected item-total correlation, min-max 0.59 (item 6)–0.85 (items 1 and 7) 0.63 (item 16)–0.78 (item 7)
Total scores, n 92 96
 Mean (SD) 30 (12.0) 13 (5.1)
 Min-Max 16–59 7–25
 Skewness 0.72 0.71
 Floor/ceiling effects 10/0 19/0
Cronbach’s alpha 0.96 0.89
ICC (95% CI) 0.92 (0.88–0.95) 0.91 (0.86–0.94)
SEMa (% of possible scoring range) 3.4 (7) 1.6 (7)
SEMb (% of possible scoring range) 2.5 (5) 1.7 (8)
SDDc (% of possible scoring range) 9.6 (20) 4.3 (20)
SDDd (% of possible scoring range) 6.8 (14) 4.7 (21)
  1. FES-I Falls Efficacy Scale-International, SEM Standard Error of Measurement, SDD Smallest Detectable Difference
  2. Possible scoring ranges: Original FES-I 16–64, Short FES-I 7–28; higher = worse
  3. aBased on ICC, using the formula SEM = SD baseline \( \times \sqrt{1- ICC} \)
  4. bBased on Cronbach’s alpha, using the formula SEM = SD baseline \( \times \sqrt{1- Cronbac{h}^{\prime } s\ alpha} \)
  5. cBased on the ICC-based SEM, using the formula \( SDD= SEM\times 1.96\times \sqrt{2} \)
  6. dBased on the Cronbach’s alpha-based SEM, using the formula\( SDD= SEM\times 1.96\times \sqrt{2} \)