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Table 6 Kappa statistics for food-frequency questionnaires (FFQ1 and FFQ2) for reproducibility

From: Reproducibility and comparative validity of a food frequency questionnaire for Australian children and adolescents

Energy & Nutrients FFQ1 vs FFQ2
(n = 101)
  Weighted kappa % correctly classified into same quintile % classified within one quintile % grossly misclassified Strength of agreementa
Energy (kJ) 0.42 ** 30 69 1 Moderate
Protein (g) 0.48 ** 30 79 4 Moderate
Fat (g) 0.47 ** 34 71 1 Moderate
Sat Fat (g) 0.43 ** 32 72 3 Moderate
Poly Fat (g) 0.44 ** 37 69 4 Moderate
Mono Fat (g) 0.45 ** 29 74 2 Moderate
Carbohydrate (g) 0.37 ** 30 67 3 Fair
Sugars (g) 0.36 ** 23 68 4 Fair
Fibre (g) 0.44 ** 34 73 5 Moderate
Thiamin (mg) 0.41 ** 34 66 4 Moderate
Riboflavin (mg) 0.41 ** 30 68 4 Moderate
Niacin (mg) 0.54 ** 36 77 2 Moderate
Niacin equiv (mg) 0.53 ** 39 77 3 Moderate
Vitamin C (mg) 0.42 ** 32 67 0 Moderate
Folate (μg) 0.41 ** 36 72 4 Moderate
Vitamin A (μg) 0.38 ** 36 63 3 Fair
Retinol (μg) 0.47 ** 36 72 2 Moderate
Betacarotene (μg) 0.49 ** 33 70 1 Moderate
Magnesium (mg) 0.41 ** 28 70 4 Moderate
Calcium (mg) 0.45 ** 27 68 3 Moderate
Iron (mg) 0.41 ** 28 66 3 Moderate
Zinc (mg) 0.49 ** 32 75 3 Moderate
  1. Kappa statistics undertaken on unadjusted (crude) data.
  2. * denotes p-value < 0.05; ** denotes p-value < 0.01
  3. a Landis and Koch classification (Landis and Koch 1977)
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