Table 1.

Methodological criteria for the translation process and cross-cultural validation [9]

Item	Methodological Criteria
1	Was the percentage of missing items given?
2	Was there a description of how missing items were handled?
3	Was the sample size included in the analysis adequate?
4	Were both the original language in which the HR-PRO instrument was developed,
	and the language in which the HR-PRO instrument was translated described?
5	Was the expertise of the people involved in the translation process adequately described?
	e.g. expertise in the disease(s) involved, in the construct to be measured, or in both languages
6	Did the translators work independently from each other?
7	Were items translated forward and backward?
8	Was there an adequate description of how differences between the original and
	translated versions were resolved?
9	Was the translation reviewed by a committee (e.g. original developers)?
10	Was the HR-PRO instrument pre-tested (e.g. cognitive interviews) to check interpretation,
	cultural relevance of the translation, and ease of comprehension?
11	Was the sample used in the pre-test adequately described?
12	Were the samples similar for all characteristics except language and/or cultural background?
13	Were there any important flaws in the design or methods of the study?
14	for CTT: Was confirmatory factor analysis performed?
15	for IRT: Was differential item function (DIF) between language groups assessed?

CTT = Classical Test Theory, IRT = Item Response Theory