Objective  To develop a nutrition health literacy questionnaire for pupils of different grades based on item response theory and to validate the questionnaire with the Rasch model.

  Methods  An index system for evaluating nutrition health literacy among pupils was established through literature study on researches and reports published at home and aboard and expert consultation for the complication of nutrition health literacy questionnaires for pupils of grade 1 – 2, 3 – 4, and 5 – 6. The developed questionnaires were then assessed among 1 074, 1 045 and 553 pupils of the three grade groups recruited with stratified random cluster sampling at 8 elementary schools in Beijing municipality, Xining city of Qinghai province and Taiyuan city of Shanxi province during June – July 2021. Based on Rasch model, the questionnaires' item discrimination, item reliability and item fitting were validated with unidimensional test, Wright map and other indicators using Winsteps software.

  Results  Valid responses were collected from 1 066, 921 and 543 pupils of the three grade groups, with an overall efficient rate of 94.7%. The questionnaires for the three grade groups were all consistent with the one-dimensional hypothesis and most of the items of the questions were of high goodness of fit. For the questionnaire towards pupils of grade 1 – 2, 3 – 4, and 5 – 6, the item discrimination indexes were 9.57, 6.03, and 13.68; the item reliability indexes were 0.99, 0.97, and 0.99; and the difficulty indexes were 2.72, – 0.18, and – 0.42, respectively, indicating a higher difficulty of the questionnaire for pupils of grade 1 – 2 and a lower difficulty of questionnaires for pupils of grade 3 – 4 and 5 – 6.

  Conclusion  The developed nutrition health literacy questionnaire for pupils of different grades fits with the Rasch model well and is of good reliability and discriminability; the questionnaire could be used in relevant surveys in pupils.