The importance of rating scales in measuring patient-reported outcomes

Table 2 Dysfunctional rating scales

Attributeunderassessment	Questionnaire(Questionnumber)	Number ofcategories	Categorieslabelled	Number of orderedthresholds/Totalnumber of thresholds	Misfitting items/Total items	Reasons fordysfunction
Difficulty
	IVI (1–19)	6	✓	3/5	1/19	Poorly definedcategories (overlappingcategories)
	ADVS (1bc–19 bcexcept 6 and 7bc)	5	✓	3/4	6/17	Question format(complicated layout dueto branching question)
Others
Limitation	HVAT (1ab-10ab)	10	X	6/10	2/10	Too many categories(multiplicative scale)
Global rating(Health)	NEIVFQ (A1, A2)	10	X	8/9	0/2	Too many categories andunlabelled
True/False	NEIVFQ (20–25,A12, A13)	5	✓	2/4	6/8	Use of neutral (‘unsure’)middle category
Apprehension	ADVS (6bc, 7bc)	5	✓	3/4	0/2	Complicated questionformat (complicated layout due to branchingquestion)
Descriptive	ICS (1)	4 (3^rd categorynot used)	✓	0/2	1/1	Complicated questionformat (complicated layout due to branchingquestion)
	VSQ (16)	3	✓	1/2	1/1	Complicated questionformat (very longdescription ofcategories)

For non-abbreviated name of the PROs, please refer Table 1.
Rating scale labels for above PROs are:
Difficulty
IVI (1–19)- Not at all, hardly at all, a little, a fair amount, a lot, cannot do because of eyesight; ADVS (1bc-19bc, except 6bc and 7bc)–No difficulty at all, a little difficulty, moderate difficulty, extreme difficulty, unable–yes (go to next question), no (go to next question).
Others
HVAT (1A-10B)- Part A: Not at all limited, slightly limited, somewhat limited, moderately limited, severely limited; Part B- I have no visual or physical limitations; none due to eyesight, some due to eyesight, half due to eyesight, most due to eyesight/all due to eyesight; NEIVFQ(20–25,A12,A13)- Definitely true, mostly true, not sure, mostly false, definitely false; NEIVFQ(A1,A2)- Worst to best (unlabelled); VSQ (16)- No, I have not had to give up work, I have not had to give up work but I am having difficulty because of my eyesight, I am retired/gave up work because of trouble with my eyesight; ADVS (6bc, 7bc)- No apprehension at all, a little apprehension, moderate apprehension, extreme apprehension, unable–yes (go to next question), no (go to next question); ICS (1)- Yes, No, If yes–none, spectacles, hand, stand magnifiers, others.

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