Iterative Development and Validation of an Innovative Smartphone-Based Dietary Assessment Tool: Traqq

The integration of technology significantly improved self-reported dietary assessment methods such as food frequency questionnaires (FFQ), food records, and 24h-recalls. However, memory-related measurement error is one of the aspects that still negatively influences the accuracy of dietary assessment.


This is where new smartphone technologies and Ecological Momentary Assessment (EMA) approaches provide a unique opportunity to further improve the accuracy of dietary assessment. More specifically, EMA offers the opportunity to deviate from traditional 24hRs to shorter recall periods (e.g., 2-hours, 4-hours).

About Traqq

Traqq is a flexible smartphone-based dietary assessment tool developed by nutrition scientists from the Division of Human Nutrition and Health of Wageningen University & Research. In order to facilitate tailoring to specific research questions, the app can be used as a food record or recall.

The recall-module is also flexible in terms of the reporting window; enabling 1-hour recalls up to 24hRs. Within the current study we are exploring the use of an innovative 2-hour recall (2hR) approach for (near) real-time data collection. A 2-hour reporting period minimizes the reliance on memory, takes less time to complete and thus should have a lower burden for the respondent.

The 2hR approach is flexible and can be used to assess actual food intake by sending consecutive 2hRs prespecified full-days or dayparts, depending on the research question. 2hRs can also be used to assess habitual intake by sending random 2hRs over a longer period of time. However, an adequate sampling scheme is crucial to ensure equal coverage of all eating occasions.


The aim of this study is to evaluate different 2hR sampling schemes in terms of accuracy, usability, perceived burden, compliance and participant preferences.

Research design

The study consists of three parts:

  1. Evaluation of the accuracy of the full 2hR-days approach for assessing actual intake of food groups, energy, and nutrients compared to traditional 24hRs and urinary biomarkers.
  2. Evaluation of the accuracy of the random 2hR approach for assessing habitual intake of food groups, energy, and nutrients compared to a traditional FFQ and blood concentration markers.
  3. Evaluation of the usability, perceived burden, compliance and participants preferences of the different 2hR sampling schemes compared to the traditional 24hRs and FFQ.

Key publications