What to ask in a self-administered dietary assessment website: The role of professional judgement

Abstract

Background: Professional judgement is a key component of questionnaire development, subjective in nature and rarely reported in this context. It is required in dietary questionnaires to delimit the size whilst retaining quality of the data. Objectives: To describe the nature and extent of professional judgement involved in developing a food database to include in a web-based self-administered dietary assessment. Methods & materials: Professional judgement was applied in tandem with a stepwise statistical analysis of hierarchically reported foods in the Australian National Nutrition Survey (NNS95). Statistical analyses determined foods commonly consumed and eaten together and three different forms of cluster analysis were then used to group foods that were most similar in macronutrient content. Professional judgement was required to interpret these groupings and determine the most suitable clustering technique. Face validity of the resulting food groups was determined by recognition of the food name by experienced dietitians, as usually reported in a diet history interview. Results: Applying professional judgement to differentiate between foods after the cluster analysis resulted in an increase from 370 to 501 food groups. A final three-level hierarchy of 19, 103 and 422 groups in the new database compared with 21, 106 and 370 groups of NNS95 was developed. Conclusions: The use of professional judgement in database development is an important step when they are to be used in self-adminstered assessments. It ensures foods are not only nutritionally appropriate but also conceptually appropriate for recognition by a layperson.

Identification of food groups for use in a self-administered, computer-assisted diet history interview for use in Australia

“…Following advice and expertise of web and graphic designers some food groups needed to be separated further to allow friendly on-screen display. This data has been reported elsewhere (Probst and Tapsell, 2007a).…”

“…Dendrograms were produced to help identify food items or groups of food items within the 370 NNS95 food groups which did not appear to fit in the original (Probst and Tapsell, 2007a). Tables showing possible options …”

“…The creation of a computer-assisted diet history website, known as DietAdvice, which contains a database of foods and associated nutrient profiles, was undertaken from -2005(Probst et al, 2007, Probst and Tapsell, 2007b. The website was developed to capture self-administered reporting of usual dietary intake.…”

“…In this study, hierarchical cluster analysis was used as a tool to help inform decision-makers of the compositional similarity between foods, so that foods which were compositionally most similar were grouped together. As some foods which are compositionally similar are conceptually dissimilar, for example custard and egg noodles, professional judgement was then used to identify conceptually similar foods (Probst and Tapsell, 2007a). …”

Updating the DietAdvice website with new Australian food composition data

“…Professional judgement was applied to the results to re-group the foods based on both nutritional and conceptual similarities (Probst and Tapsell, 2005). The final developmental stage was face-validity testing by a group of dieticians.…”