Tool Library Tool Information
Validation Information: Oxford WebQ
Development and evaluation of the Oxford WebQ, a low-cost, web-based method for assessment of previous 24 h dietary intakes in large-scale prospective studies
Objectives: To describe the development of the Oxford WebQ, a web-based 24h dietary assessment tool developed for repeated administration in large prospective studies; and to report the preliminary assessment of its performance for estimating nutrient intakes.
Design: We developed the Oxford WebQ by repeated testing until it was sufficiently comprehensive and easy to use. For the latest version, we compared nutrient intakes from volunteers who completed both the Oxford WebQ and an interviewer-administered 24h dietary recall on the same day.
Setting: Oxford, UK.
Subjects: A total of 116 men and women.
Results: The WebQ took a median of 12.5 (interquartile range: 10.8-16.3) min to self-complete and nutrient intakes were estimated automatically. By contrast, the interviewer-administered 24h dietary recall took 30 min to complete and 30 min to code. Compared with the 24h dietary recall, the mean Spearman's correlation for the 21 nutrients obtained from the WebQ was 0.6, with the majority between 0.5 and 0.9. The mean differences in intake were less than ±10% for all nutrients except for carotene and vitamins B12 and D. On rare occasions a food item was reported in only one assessment method, but this was not more frequent or systematically different between the methods.
Conclusions: Compared with an interviewer-based 24h dietary recall, the WebQ captures similar food items and estimates similar nutrient intakes for a single day's dietary intake. The WebQ is self-administered and nutrients are estimated automatically, providing a low-cost method for measuring dietary intake in large-scale studies.
Total number of nutrients validated: 20
Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:
- Saturated Fat
- Mono-unsaturated Fat
- Poly-unsaturated Fat
- Non‐starch polysaccharides(NSP)
- Folic Acid
- Vitamin B12
- Vitamin C
- Fruit & Vegetables
- Urinary Nitrogen
To find information on the other validated nutrients please read the validation study.
- Macronutrients: 8
- Micronutrients: 11
|Comparator||Lifestage||Sex||Nutrient Measured||Mean Difference||Standard Deviation||Correlation Coefficient||Cohen's Kappa Coefficient||Percentage Agreement||Percentage Agreement Categories||Lower Limits of Agreement||Upper Limits of Agreement|
|24hr Recall||Adults||Both||Energy (kcal)||3||555||0.58 (S)||50||3||-1108||1113|
|Energy (kJ)||11||2323||0.58 (S)||50||3||-4636||4658|
|Protein (g)||-1||23||0.59 (S)||60.3||3||-47||45|
|Fat (g)||4||33||0.57 (S)||51.7||3||-62||69|
|Saturated Fat (g)||-1||12||0.64 (S)||57.8||3||-24||22|
|PUFA (g)||1||9||0.54 (S)||50.9||3||-17||20|
|Carbohydrates (g)||-5||72||0.66 (S)||57.8||3||-149||139|
|Total Sugars (g)||-4||44||0.66 (S)||58.6||3||-92||83|
|Fibre (NSP) (g)||1||7||0.63 (S)||56||3||-12||15|
|Calcium (mg)||-8.8||338.4||0.60 (S)||55.2||3||-685.6||668|
|Iron (mg)||0.4||4.8||0.62 (S)||59.5||3||-9.1||9.9|
|Folate (µg)||24.5||119.2||0.58 (S)||48.3||3||-213.9||262.9|
|Vitamin B12 (µg)||1.6||3.5||0.58 (S)||60.3||3||-5.4||8.6|
|Vitamin C (mg)||-7||97.3||0.62 (S)||60.3||3||-201.5||187.5|
Some results have been calculated using statistical techniques based on the published data.
For further information on statistical terms click on Statistical tests used in validation studies
All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.
- # Adjusted
- † Energy adjusted.
- ‡ For loge-transformed, energy-adjusted nutrient intakes.
- ^ Adjacent included.
- ᵟ Participants provided identical responses.
- (w) = Weighted.
Liu B, Young H, Crowe FL, Benson VS, Spencer EA, Key TJ, et al. Development and evaluation of the Oxford WebQ, a low-cost, web-based method for assessment of previous 24 h dietary intakes in large-scale prospective studies. Public health nutrition. 2011 Nov 1;14(11):1998-2005.