Development of a performance-rating scale for a nutrition knowledge test developed for adolescents

Abstract

Objective: The objectives of the present study were to (i) develop and validate a norm-referenced performance-rating scale to interpret a nutrition knowledge test developed for urban adolescents and (ii) develop a prototype for other researchers to follow when developing nutrition knowledge tests. Design: For norm development the nutrition knowledge test (questionnaire) was administered to a sample representative of the questionnaire target group, referred to as the norm group. These included 512 adolescents in grades 8 (n 158), 10 (n 149) and 12 (n 205) at three randomly selected schools in Soweto and Johannesburg. The performance scores (in percentages) obtained by the norm group were transformed to Z-scores which were categorised into stanines using established Z-score cut-off points. For validation purposes the questionnaire was completed by 148 volunteers: sixty university dietetics students, nineteen nonnutrition university students and sixty-nine primary-school teachers. Results: As required of an ideal norm group, the Z-scores formed a normal distribution (a bell-shaped curve). To facilitate interpretation of the results, the Z-score cut-off points for these categories were transformed back to performance scores (percentages) so that the performance of a testee could be interpreted directly from his/her performance in percentage. As is recommended, the nine stanine categories were reduced to five: very poor, fair/below average, good/average, very good/ above average and excellent. The discriminatory validity of the norms was substantiated by showing that groups with known nutrition knowledge levels were rated appropriately and that the performance ratings of these groups differed significantly, with university dietetics students scoring 98?3 %, primary-school teachers 20?3 % and non-nutrition university students 31?6 %. Conclusions: The norm-referenced performance-rating scale can be used with confidence to interpret the performance score achieved by a testee on the nutrition knowledge test developed for urban adolescents in South Africa. The methodology used in the study serves as a prototype for other researchers who are developing knowledge tests.

Consumer knowledge and use of food and nutrition labelling in South Africa: A cross‐sectional descriptive study

“…The total percentage knowledge scores calculated were interpreted based on a performance-rating scale developed by Whati, Senekal, Steyn, Lombard, and Nel (2009).…”

Is a Nutrition Education Intervention Associated with a Higher Intake of Fruit and Vegetables and Improved Nutritional Knowledge among Housewives in Mauritius?

“…Age is positively linked to nutrition knowledge and the older age groups are known to be more health conscious and more interested in healthy eating, which in turn could result in them acquiring more nutrition knowledge [18]. Also, older respondents have higher nutrition knowledge compared to their younger counterparts as they have been exposed to more nutritional information [19]. In their study, Bhurosy and Jeewon [20] also reported higher knowledge scores in older adults after a nutrition education program.…”

Dietary assessment in the transition to adulthood

“…In this issue, Whati et al . ( 1 ) address this challenge in a paper that describes the development and validation of a norm-referenced performance-rating scale to interpret a nutrition knowledge test for use among urban adolescents in South Africa. The methodology they outline serves as a useful prototype for developing knowledge tests in this and other contexts.…”