Table 1.

Characteristics of scales and items in the questionnaire

Scale/item	# items	Cronbach’s α/Pearson’s coefficient (r)	Examples of items, answer categories and score range
Outcomes
Child’s snacking behaviour	4	-	How many days a week does your child eat snacks (crisps, cheese cubes etcetera or sweets)? Never (0) – every day (7). How many portions (crisps, cheese cubes etcetera or sweets) does your child eat per day? 1-2 portions a day (1) – more than 4 portions a day (3)
Child’s outdoors playing	2	-	How many days a week does your child play outdoors (outside school time) Never (0) – every day (7). How long does your child generally play outdoors? Less than half an hour per day (1) – more than 3 hours per day (5).
Intention snack intake	1	-	For the next six months, I plan to make sure my child does not eat too many sweets and snacks. Certainly not (-2) – certainly (2)a
Intention playing outdoors	1	-	Do you plan to be alert to see that your child plays outdoors enough to prevent or diminish overweight in the next six months? Certainly not (-2) – certainly (2)
Distal factors
Beliefs about genetic causes of overweight	8	α =0.75	A person’s physique is hereditary. Totally disagree (-2) – totally agree (2)
Perceived child weight	2	r = 0.83	What do you think of your child’s weight at this moment? Compared to other children of his/her age, I find my child…. Far too heavy (-2) – far too light (2)
Monitoring (CFQ)b	3	α = 0.91	How much do you keep track of the sweets (candy, ice cream, cream cake) that your child eats? Never (-2) – Always (2)
TPB factors
Attitude snack intake	6	α = 0.61	I think it’s alright to watch my child at all time so he/she does not eat too many sweets and snacks. Totally disagree (-2) – totally agree (2)
Subjective social norm snack intake	3	α = 0.85	My partner thinks that I should be alert and see that my child does not eat too many candies and snacks. Certainly not (-2) – certainly (2)
Perceived behavioural control snack intake	2	r = 0.42	Do you think that you will succeed in continuing to watch your child so he/she does not eat too many sweets and snacks if he/she keeps asking for snacks. Certainly not (-2) - certainly (2)
Attitude playing outdoors	6	α = 0.45	If I make sure my child plays outdoors enough, he/she will not become/be less overweight. Totally disagree (-2) – totally agree (2)
Subjective social norm playing outdoors	3	α = 0.91	My parents think that I should be alert and make sure my child plays outdoors enough. Certainly not (-2) – certainly (2)
Perceived behavioural control playing outdoors	2	r = 0.50	Do you think that you will succeed in getting your child to play outdoors enough if he/she wants to watch TV and he/she keeps on at you? Certainly not (-2) - certainly (2)

^a The response categories of TPB-items, and the items of the scales perceived child weight and beliefs about genetic causes of overweight, comprised five options with a neutral option in the middle, except for attitude items which had ‘slightly agree’ as middle response option.

^bSubscale of Child Feeding Questionnaire (CFQ) [33].