Measurement implies assigning numbers to objects or events. In our case, the numbers “weight” responses to questions, so that saying “Yes” to a question on being able to walk out of doors will receive a particular numerical score, instead of merely counting as one “Yes” reply.
Where do these numbers come from?
Many variants. For example:
* Half p for that category plus p for category below
1 2 3 4 5 6
I can run a mile TX X X X X
I can do the grocery shopping T T X X X X
I can walk one block TT TX X X
I can rise from an armchair TT T T X X
I can use the toilet without assistance T T T T T X
score 5 4 3 2 1 0