Table 7 Coding framework for the analysis of response issues

Comprehension

• Odd wording

Participants find the terms or sentence unusual or odd

• Difficult wording

Participants find the terms or sentence difficult because of unfamiliar terms/phrases or struggles with the item’s structure

Recall

• Recall difficulties

Participants find it difficult to recall events to be able to give an answer to the item

Interpretation

• Difficult interpretation of item

Participants express that they do not understand the meaning of an item

• Inconsistency with previous item

Participants’ answer is inconsistent with a previous item

• Wrong interpretation of item

Participants interpret the item in a way that is different than what was intended by the developer of the instrument

• Wide interpretation of the item

Participants focus on more aspects than the ones included in the item by the developer of the instrument

• Narrow interpretation of item

Participants focus on just one aspect of the item or is unsure about the focus of the item

Response Option Selection

• Double-barreled questions

Participants feel that different response options apply to different aspects of the item

• Response options partly applicable

Participants indicate that one part of the response option fits their situation, and one part does not

• Response option is inappropriate

Participants feel that a response option is inappropriate or judgmental

• Irrelevant response options

Participant does not want to answer any of the given response options

• Missing intermediate

Participant feels that there is a gap between two consecutive response options

• Similar response options

Participant feels that two response options are similar

• Disagreement with order of options

Participant does not agree with the order of two response options

• Inconsistent response

Response option chosen did not match what the participants said or the participants’ situation

Acceptability

• Item inappropriate/ judgmental

Participants feel that a question is inappropriate or judgmental and should not be asked

Relevance

• Similar items

Participants could not see the difference between items or feeling that the items are excessively similar

• Item irrelevant

Item not relevant to the participants

• Important QoL asp. missing

Participant feels that the measure misses important aspects of QoL