Table 3.

Descriptive analyses, internal consistency analysis, test–retest reliability, standard error of the measure, minimal detectable change and construct validity of the 30-item and 10-item Icon-FES questionnaire.

	30-item Icon-FES	10-item Icon-FES
Mean score (SD)*	51.6 ± 12.9	17.9 ± 4.6
Minimum score (floor effect), n (%)	0 (0%)	4 (4%)
Maximum score (ceiling effect), n (%)	0 (0%)	0 (0%)
Cronbach's alpha	0.94	0.83
ICC2,1 (95% CI)	0.96 (0.95–0.98)	0.93 (0.90–0.95)
SEM	2.6	1.2
MDC	7.2	3.4
Skewness (SE)	0.44 (0.24)	0.20 (0.24)
Kurtosis (SE)	−0.44 (0.48)	−0.69 (0.48)
Spearman rho coefficient	0.83**	0.76**

Abbreviations: ICC, intraclass correlation coefficient; IC, confidence interval; SEM, standard error of the measurement; SE, standard error; SD, standard deviation; MDC, minimal detectable change.

^*Kolmogorov–Smirnov test revealed a p > 0.05, indicating normal distribution.

^**p < 0.001.