2.4.1 Linguistic Validation
Linguistic validation is based on the backtranslation method according to the guide sent by the Mapi Trust.4, 12 This method is also similar to Beaton et al.13 The linguistic validation of PedQL™ 3.0 EoE module consisted of these steps (Figure 1):
1. Forward translation: Creating a single reconciled Turkish version (Tr-V1): Two local professional translators independently produced a forward translation of the original items, instructions, and response choices. The expert committee consisting of two Pediatric Allergy Professors (HIEK and AB), 3 Pediatric Gastroenterology Professors (BD, SS, OEG) and 1 public health specialist (DY) got together and created the single reconciled Turkish version (Tr-V1).
2. Backward translation and comparison with the original scale (Tr-V2): A translator, native speaker of English, and bilingual (Turkish and English) translated the first reconciled version (Tr-V1) into English. The research team and the backward translator made a comparison of the backward version with the original source to detect any misunderstandings, mistranslations, or inaccuracies in the intermediary forward version. Here, minor changes were made in line with some suggestions and this second reconciled version was created (Tr-V2).
3. Evaluation of Tr-V2 with source instrument by Davis method in terms of language translation by 8 independent experts (for assessment of content validity): Expert opinion was requested from 8 academicians (independent reviewers: 2 pediatric allergists, 6 pediatric gastroenterologists) to evaluate of latest Turkish version (Tr-V2) and original tool in terms of language and cultural appropriateness. The latest Turkish version and original tool were e-mailed to the reviewers. The independent reviewers jointly analyzed the Turkish version and the original version, using the Davis technique14-16 with the main purpose of evaluating the semantic, experimental, and conceptual equivalence between the original tool and Turkish version. According to this technique, items are evaluated on a four-point scale: (a) “The item is appropriate”, (b) “The item should be slightly revised”, (c) “The item should be revised extensively” and (d) “The item is inappropriate”. The number of experts marking the options (a) and (b) is divided by the total number of experts to calculate the content validity (CnV) index (CVI) for an item. The cut-off value for this index is considered as 0.80 with a minimum consensus of 80% agreement between the reviewers.15, 17 According to the feedback of the group’s responses (expert opinions), the latest Turkish version (Tr-V2) was revised.
4. Patient testing and Expert Committee evaluation, re-evaluating the scale and making necessary correction for Final Version: We administered Tr-V2 to a sample of patients and parents to determine whether the translation (instructions, items, and response choices) is acceptable, whether it is understood in the way it is supposed to be, and whether the language used is simple and appropriate. In the patient testing, 8 teens and 8 parents responded to all the questions. After this phase, the expert committee came together again and put the scale into its final Turkish version by considering the opinions and suggestions before field testing. Turkish linguistic validation process has been completed.