NILSSON J, FRIDEN C, BUREN V, ANG BO. Development and validation of a web-based questionnaire for surveying skydivers. Aviat Space Environ Med 2011; 82:610-4. Introduction: Parachuting injuries are well-known medical problems in military and recreational skydiving. However, little is known about sub-clinical incidents such as those involving the opening shock. To date, there is no validated questionnaire for epidemiological purposes that identifies relevant exposures among skydivers. A web-based platform has been recognized as a convenient approach for data collection in the Swedish skydiving population. The present aim was, therefore, to validate such a web-based questionnaire for wide assessment of pain incidents and related risks among Swedish skydivers. Methods: Initially, a web-based questionnaire was developed and piloted with 102 skydivers. Content and face validity were then systematically assessed by an independent panel of seven experts in three developing stages before the form was finalized by the present authors in a consensus panel. The reviewers were medical (N = 5) and skydiving (N = 2) experts. Content validity was rated on a four-point Likert-type ordinal scale. The item content validity index (I-CVI) was the proportion of experts rating an item as acceptable (score 3-4) while scale-CVI was the proportion of acceptable items in the questionnaire. Face validity was achieved with open-ended reviews. Results: Of the 19 items in the final web-based questionnaire, 18 reached an I-CVI of 0.86 or higher, with the last item reaching an I-CVI of 0.71. The overall scale-CVI was 0.95. Face validity for the final version was assessed as 'good' or 'really good'. Conclusions: The present web-based questionnaire is considered valid for further use in studies investigating epidemiological and clinical aspects among skydivers.