In the case of subjective well-being measures, three key aspects of question wording are particularly important. The first issue is that of question comprehension. Establishing what a subjective self-report measure actually means for respondents is difficult - but for responses to be comparable, it is important that respondents interpret questions in a similar way.
Second, there is the issue of whether minor changes in question wording affect results in major ways. For the self-report survey method to be valid at all, it is essential that different question wording leads respondents to draw on different sources of information - so that, for example, asking respondents how happy they felt in the last 24 hours causes them to consider different information than asking them how angry they felt. Problems potentially arise, however, when different question wording is used to measure the same underlying construct. How similar question wording needs to be before it can be regarded as measuring the same thing is an essential issue for survey comparability.
The third issue is that of translatability - which includes both translatability between languages and cultures, as well as between generations and subgroups within a society. To minimise error variability, question wording needs to be understood in broadly the same way by different respondents. Certain question wordings may create particular difficulties when translated into different languages - or may have particular connotations for some groups of respondents. This potentially limits how comparable data are across different groups.