Table 2
Test-retest reliability and relative validity of the New Zealand Adolescent Food Frequency Questionnaire (NZAFFQ): Spearman’s correlation coefficients, intraclass correlation coefficients, percent correctly classified and grossly misclassified into thirds of food group intake
	Test-retest reliability (n = 52)(FFQtime1 vs. FFQtime2)				Relative validity (n = 41) (FFQtime1 vs. 4DFR)
Food Groups	SCC	ICC	% CC	% GM	SCC	% CC	% GM
Fruit juice or cordials	0.46	0.57	61	10	0.40	46	10
Artificially sweetened drinks	0.82	0.68	80	4	0.25	56	24
Tea or coffee	0.85	0.70	88	4	0.43	63	20
Milky or chocolate drinks	0.75	0.81	67	2	0.62	46	5
Sugar-added drinks	0.77	0.37	71	4	0.32	49	17
Rice, pasta or noodles	0.47	0.80	75	25	0.44	37	17
Non-white bread or bun1	0.80	0.72	61	4	0.36	45	13
Breakfast cereals	0.78	0.74	56	0	0.67	56	10
White bread or bun	0.78	0.64	73	4	0.40	37	10
Cheese	0.67	0.58	58	2	0.40	41	10
Non-standard milk2	0.87	0.79	78	0	0.59	55	8
Standard milk3	0.83	0.78	67	0	0.70	61	2
Yoghurt	0.79	0.84	75	0	0.46	54	10
Poultry	0.63	0.34	69	6	0.46	51	7
Eggs	0.80	0.53	77	0	0.52	41	5
Nuts or seeds	0.71	0.73	71	6	0.24	54	22
Meat alternatives	0.54	0.92	83	17	0.55	78	22
Legumes	0.50	0.45	53	6	0.42	59	17
Red meat and processed meat	0.60	0.26	62	8	0.13	41	15
Fish and seafood	0.76	0.67	65	2	0.34	41	15
Fruits	0.58	0.83	58	8	0.27	44	10
Cruciferous vegetables	0.72	0.64	63	4	0.26	46	20
Green leafy vegetables	0.74	0.77	69	4	0.27	44	17
Red or yellow vegetables	0.60	0.70	46	2	0.08	27	12
Marrow-like vegetables	0.59	0.76	56	6	0.39	59	17
Potatoes	0.56	0.61	71	6	0.25	27	7
Other vegetables	0.65	0.56	60	4	0.40	59	10
Sweet bakery products4	0.65	0.62	67	10	0.56	44	12
Sweet snack bars5	0.65	0.56	60	4	0.58	61	5
Nut spreads	0.79	0.73	73	2	0.37	59	20
Ice-cream	0.64	0.79	58	4	0.42	51	5
Sweets6	0.79	0.54	77	2	0.18	39	20
Convenience foods7	0.56	0.67	67	10	0.04	46	29
Savoury biscuits and crisps	0.70	0.70	62	4	0.29	39	12

Abbreviation: first administration of the New Zealand Adolescent Food Frequency Questionnaire (FFQtime1), second administration of the New Zealand Adolescent Food Frequency Questionnaire (FFQtime2), four-day estimated food records (4DFR), Spearman’s correlation coefficients (SCC), intraclass correlation coefficients (ICC), percent correctly classified (%CC), percent grossly misclassified (%GM).

¹ Brown or wholegrain bread.

² Low-fat milk, trim milk, calcium-fortified trim milk, rice milk, soy milk.

³ Whole-fat milk.

⁴ Sweet biscuits, cakes, muffins, doughnuts, fruit pies.

⁵ Muesli bars, fruit bars rice bubble bars.

⁶ Lollies, chocolate confectionery.

⁷ Pies, sausage rolls, pizza.

Wong et al. Nutrition Journal 2012 11:65   doi:10.1186/1475-2891-11-65