Saving time and effort: Best practice for adapting existing patient-reported outcome measures in hepatology

Table 4 Categories of equivalence

Categories
Conceptual equivalence	The domains of the questionnaire have the same relevance, meaning and importance in both cultures
Item equivalence	Individual items have the same relevance in both cultures
Semantic equivalence	The meaning of the items is the same in both cultures
Operational equivalence	The questionnaire can be used in the same way by the target population in both cultures
Measurement equivalence	The two versions have similar psychometric properties
Functional equivalence	This is meant as a summary category of the preceding five categories. It is an overall statement that identifies if both versions “do what they are supposed to do equally as well”