Was the percentage of missing items given?
Was there a description of how missing items were handled?
Was the sample size included in the analysis adequate?
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?
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
Did the translators work independently from each other?
Were items translated forward and backward?
Was there an adequate description of how differences between the original and
translated versions were resolved?
Was the translation reviewed by a committee (e.g. original developers)?
Was the HR-PRO instrument pre-tested (e.g. cognitive interviews) to check interpretation,
cultural relevance of the translation, and ease of comprehension?
Was the sample used in the pre-test adequately described?
Were the samples similar for all characteristics except language and/or cultural background?
Were there any important flaws in the design or methods of the study?
for CTT: Was confirmatory factor analysis performed?
for IRT: Was differential item function (DIF) between language groups assessed?