Translation of the Social Difficulties Inventory (SDI-21) into three South Asian languages and preliminary evaluation of SDI-21(Urdu).

Purpose: In the United Kingdom, cross-cultural adaptation of questionnaires would allow for inclusivity in assessment in cancer clinics for non-English speakers. The aim was to translate the Social Difficulties Inventory (SDI-21) into Urdu, Punjabi and Hindi and undertake preliminary evaluation of translated versions.
Methods: The study comprised three stages: (1) translation/back translation and evaluation of cultural equivalence of the SDI-21, (2) south Asian (SA) patient evaluation of SDI-21 translations and (3) evaluation using Rasch analysis comparing English and Urdu SDI-21 from data pooled from this and three other studies.
Results: Forward/backward translation resulted in minor amendments particularly in forward translation of SDI-21(Hindi). The majority of the 55 patients interviewed found the SDI-21 acceptable and clear, resulting in no amendments (all versions). Rasch analysis demonstrated good fit. Differential item functioning (DIF) was found for one item, in the comparison of white English (WE)- and SA Urdu-speaking groups. Detailed DIF analysis comparing self-completion and read-aloud administration by language group demonstrated this DIF only held for the comparison between SA English speakers (self-completion) and SA Urdu (read out).
Conclusions: Translated versions are culturally and linguistically acceptable. The SDI-21 (Urdu) performs similarly to the English version when self-completed.