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Validation Information: Oxford WebQ

Liu 2011

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.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Full Nutrient
Tool Type
24 Hour Recall
Timeframe Tool Measures info
1 Day
Portion Size Measures info
The participants select the amount consumed over the previous 24 hours.
Reporting Method info
Format info
Supplements Measured
Not Reported
Administration Method info

Study Information

Study Location
Oxford, England
Associated Nutrient Database
McCance & Widdowson's The Composition of Foods, 5th and 6th edition and supplements
Comparator Validated Against
24hr Recall


Sample Size
Age of Population

Range: 19-82 years

Mean: 42

Other Notable Characteristics

Total number of nutrients validated: 20 info

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:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Energy
  • Macronutrients: 8
  • Micronutrients: 11
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info 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.