Table 3 Themes of translation issues

Lack of matching definitions with items across languages

Equivocal items with precise definitions

Anxiety item bank: ‘I was afraid of going to school’, where the item could mean both being in school and traveling to school. The item was translated in accordance to the item definition^a and the concept of being in school. (5)

Equivocal items without precise definitions

Physical activity item bank: ‘How many days did you run for 10 min or more?’. Whether it refers to 10 min of continuous running or 10 min in total during the day is not clear. The item was translated to 10 min of continuous running. (1)

Problems related to language, vocabulary and cultural differences

Adjectival agreement on intensity levels of the concept to be translated

Anxiety item bank: The translation of the word ‘scared’ used in the Anxiety item bank was translated to ‘rädd’. The word ‘rädd’, can be back-translated to either ‘scared’ or ‘afraid’. In Swedish, the grade difference between afraid and scared is more difficult to clearly illustrate using only a single word. (2)

Culturally specific idiomatic phrases

Physical activity item bank: ‘How many days did you exercise or play so hard that your muscles burned?’. ‘Muscles burned’ is an idiomatic phrase in English and this could not be translated directly to Swedish. Instead, this was translated to ‘How many days did you exercise or play so much that you got aching muscles?’. (3)

Cultural differences of measurements

Pain interference item bank: ‘It was hard for me to walk one block when I had pain’. The informal American English measurement of ‘one block’ has no Swedish equivalent. The translation must therefore relate to either the exact distance of a block (if such an exact measure exists) or an approximation. The Swedish translation used both: ‘it was difficult for me to walk a short distance (about 100 m) when I was in pain’. (1)

Difficulties in adaption to age-appropriate language

Comprehensibility of the items changes in the translation process

Anger item bank: I felt upset’ the most precise translation of the item ‘I felt upset’ in the Anger item bank was ‘upprörd’ which was difficult to understand for children of younger age. Hence, this item was instead translated to ‘I felt both angry and sad’. (4)

Acceptance of the items for all age groups

Peer relationships item bank: ‘Other kids wanted to be with me’ was not accepted by teenagers until ‘kids’ was replaced by ‘others my age’. This phrase was then reused in other items for consistency and thus avoided the problem of having to use the word ‘child’. (8)