Table 2.

ICF categories: (a) as originally denoted and described in words, numerals, percentages and mid-point scores for each categorical percentage-span; and (b) as backcoded in this study.

ICF (in words)	ICF (in categories)	ICF (in percentage terms)	EDAD 2008 categories	Mid-point score
No difficulty	0	0%-4%	No or mild difficulty	12%
Mild difficulty	1	5%-24%.
Moderate difficulty	2	25%-49%	Moderate difficulty	37%
Severe difficulty	3	50%-95%	Severe difficulty	72.5%
Complete difficulty	4	96%-100%	Complete difficulty	98%

Since the EDAD 2008 drew no distinction between 0 and 1, these two options were combined as 0%-24%, which matches a mid-point score of 12%

A global score was obtained for capacity measurements but not for performance. To calculate such a global score, a total of 32 variables were -not always unequivocally- selected to build 32 ICF categories from the ICF checklist (Tables 1 and 3). Answers of inapplicable and missing values were replaced by 1 (no or mild difficulty).