Table 3.

Attenuation Factors for and Correlations Between Daily Dietary Intake Derived From Self-Report Tools and Estimated True Longer-Term Intake for a Single Application of the Oxford WebQ, London, United Kingdom, 2014–2016^a

Nutrient Measure	Attenuation Factor	95% CI	Correlation With True Intake	95% CI	Mean Difference From Reference Tool, %	95% CI
Nutrient intake, g
Protein
Oxford WebQ	0.27	0.17, 0.36	0.40	0.27, 0.52	12	6, 19
MPRb	0.33	0.24, 0.43	0.46	0.36, 0.57	8	3, 14
Potassium
Oxford WebQ	0.31	0.18, 0.44	0.34	0.20, 0.47	53	42, 64
MPR	0.35	0.22, 0.48	0.37	0.25, 0.49	47	37, 57
Total sugars
Oxford WebQ	0.31	0.18, 0.44	0.33	0.20, 0.46	−25	−18, −32
MPR	0.16	0.01, 0.30	0.15	0.01, 0.30	−32	−25, −39
Total energy expenditure, MJ
Oxford WebQ	0.22	0.12, 0.33	0.32	0.18, 0.46	−22	−17, −27
MPR	0.30	0.17, 0.42	0.36	0.22, 0.49	−22	−18, −27
Nutrient densityc, g/MJ
Protein
Oxford WebQ	0.34	0.17, 0.51	0.29	0.16, 0.42	46	37, 55
MPR	0.26	0.10, 0.42	0.23	0.09, 0.36	41	32, 50
Potassium
Oxford WebQ	0.33	0.12, 0.54	0.23	0.09, 0.37	99	83, 115
MPR	0.41	0.23, 0.59	0.33	0.19, 0.46	91	77, 106
Total sugars
Oxford WebQ	0.32	0.15, 0.50	0.27	0.13, 0.41	−3	8, −12
MPR	0.16	−0.03, 0.35	0.13	−0.02, 0.28	−12	−1, −21

Abbreviations: CI, confidence interval; MPR, multiple-pass recall.

^a Data for all dietary measures and estimates were log-transformed.

^b Interviewer-based multiple-pass 24-hour dietary recall.

^c Nutrient density for protein, potassium, and total sugars was expressed in grams per MJ of total energy intake.