Fig. 1

Flow chart of 8-step methadology used to develop and validate the Nutrition for Sport Questionnaire (UNSQ). * Content Validity = the measure covers all relevant topics related to sports nutrition. † CVI = Number of experts who rated an item ‘very relevant’ or ‘relevant’ divided by total number of experts; > 0.78 is adequate. ‡ Face Validity = the measure, on face value is an adequate reflection of sports nutrition. § Difficulty index = frequency with which items were answered correctly; <20% = too hard; >80% = too easy. ǁ Discrimination index = average score of top 10% of participants minus average score of bottom 10% of participants; > 0.3 is adequate. ¶ Distractor utility = frequency with which each multi-choice option is selected; > 5% = effective distractor. **Fit residuals between −2.5 and 2.5 indicate observed = expected responses. ††DIF assessed using ANOVA; non-significant p-value = no differences in response pattern based on participant characteristics; ‡‡ Disordered thresholds are assessed graphically. §§ Perc5% statistic <5% = scale is unidimensional (assessing one concept). ǁ ǁ SD of 0 and Mean of 1for the overall item/person interaction = perfect fit to Rasch model; a SD > 1.5 = misfit. ¶¶ Significant differences in known-group comparison scores = construct validity (questionnaire test what it is supposed to). *** Pearson’s r > 0.7 = test-retest reliability (stability overtime). ^††† KR-20 > 0.7 = Internal reliability (consistency in items)