Item response modeling: a psychometric assessment of the children’s fruit, vegetable, water, and physical activity self-efficacy scales among Chinese children

Wang, Jing-Jing; Chen, Tzu-An; Baranowski, Tom; Lau, Patrick W.C.

doi:10.1186/s12966-017-0584-x

International Journal of Behavioral Nutrition and Physical Activity

Table 3 Item description, item difficulty, and misfit item(s)

From: Item response modeling: a psychometric assessment of the children’s fruit, vegetable, water, and physical activity self-efficacy scales among Chinese children

Item	Item questions	All	Boys	8-10 yrs	Underweight	Healthy Weight	Overweight /Obesity
Fruits self-efficacy (Cronbach’s alpha = 0.86)
12	…eat 1 portion of fruit most times when you eat at a fast food place.	1.171	−0.197	−0.159	0.031	0.076	−0.107
11	…eat 1 portion of fruit at a fast food place at least one time.	1.052	−0.233	−0.149	0.063	0.073	−0.136
10	…eat 1 portion of fruit for dinner at home at least one time.	0.402	−0.085	0.075	−0.005	0.138	−0.133
3	…ask someone in your family to buy 3 fruit at least every week.	0.011	−0.001	−0.030	0.065	−0.061	−0.004
4	…eat 1 portion of fruit at lunch at least one time on a school day.	−0.049	−0.019	−0.075	0.085	−0.042	−0.043
6	…eat 1 portion of fruit for lunch most non-school days, including weekends.	−0.100	0.061	−0.018	0.009	0.003	−0.011
2	…ask someone in your family to buy 3 fruit at least one time.	−0.189	−0.051	0.029	0.053	−0.123	0.070
1	…ask someone in your family to buy your favorite fruit every week.	−0.256	0.096	0.078	−0.018	0.042	−0.023
5	…eat 1 portion of fruit for lunch at least one time on a non-school day, including weekends.	−0.400	0.096	0.090	−0.017	−0.057	0.074
8	…eat 1 portion of fruit for a snack at home at least 4 days a week.	−0.436	0.115	0.061	−0.017	−0.032	0.050
9	…ask someone in your family to serve 1 fruit instead of your usual dessert for dinner most nights.	−0.487	0.039	−0.025	−0.115	0.041	0.074
7	…eat 1 portion of fruit for a snack at home at least one time.	−0.719	0.179	0.123	−0.133	−0.057	0.190
Vegetables self-efficacy (Cronbach’s alpha = 0.85)
6	…eat 3 portions of vegetables at least 4 days a week, even when you are stressed.	0.556	−0.098	−0.102	0.308	−0.171	−0.137
7	…eat 1 portion of a vegetable most times when you eat at a fast food place.	0.267	0.017	0.012	−0.049	−0.044	0.092
2	…cut up 1 portion of a vegetable and eat it with a dip for a snack at least one time.	0.250	−0.074	−0.029	0.136	−0.062	−0.074
4	…ask someone in your family to serve 2 vegetables for dinner most nights.	0.214	0.016	0.027	−0.151	0.021	0.130
3	…ask someone in your family to serve 2 vegetables for dinner at least one time.	0.028	0.000	0.020	−0.030	0.041	−0.011
8	…eat 1 portion of a vegetable most times when you eat at a cafeteria type restaurant.	−0.110	0.095	−0.016	−0.022	0.007	0.015
5	…eat 3 portions of vegetables at least 4 days a week.	−0.363	−0.014	0.095	0.108	0.050	−0.158
1	…eat 1 portion of a vegetable at lunch at least one time on a school day.	−0.841^a	0.057^c	−0.007^e	−0.300^g	0.157^g	0.143^g
Water self-efficacy (Cronbach’s alpha = 0. 79)
5	...drink 6 glasses or bottles of water for at least one day.	0.345	−0.042	−0.049	0.303	−0.164	−0.139
4	…drink 6 glasses or bottles of water for at least 4 days a week.	0.168	−0.068	0.032	0.103	−0.087	−0.016
3	…drink only water whenever you are thirsty for at least 4 days a week.	0.167	−0.032	−0.145	−0.082	0.045	0.036
1	…drink only water whenever you are thirsty for at least one day.	−0.268	0.123	0.001	−0.258	0.135	0.124
2	…drink 4 glasses or bottles of water for at least one day.	−0.413	0.019	0.162	−0.066	0.071	−0.005
Physical Activity self-efficacy (Cronbach’s alpha = 0.91)
11	…be physically active more than 30 min for at least 4 days a week, even when the weather outside is bad.	0.748	0.035	−0.077	0.097	−0.052	−0.044
6	…ask your friends to be physically active with you more than 30 min for at least 4 days a week.	0.623	−0.067	0.058	−0.106	0.106	0.001
10	…be physically active more than 30 min for at least 4 days a week when your friends want to do something else.	0.547	−0.109	−0.124	0.028	0.009	−0.038
8	…be physically active more than 30 min for one day, even when you have lots of other things to do.	0.462	−0.006	−0.075	−0.135	0.012	0.122
7	…be physically active more than 30 min for one day, even when you have homework.	0.397	−0.019	−0.058	−0.068	0.011	0.058
9	…be physically active more than 30 min for at least 4 days a week, even when you have lots of other things to do.	0.331	0.055	−0.125	−0.024	0.052	−0.027
4	…the ability to play team sports like basketball, soccer or softball really well.	0.104	−0.357	0.014	0.057	0.163	−0.220
5	…ask your friends to be physically active with you more than 30 min for at least one day.	−0.277	0.068	0.094	0.107	0.050	−0.157
12	…be physically active more than 30 min for most nonschool days, including weekends.	−0.450	0.180	0.152	0.001	0.036	−0.038
2	…the ability to do physical activities like running, dancing, bicycling, or jumping rope really well.	−0.453	0.219	−0.108	−0.114	−0.191	0.304
3	…the ability to play team sports like basketball, soccer or softball.	−0.516	−0.395	0.133	0.286	−0.028	−0.258
1	…the ability to do physical activities like running, dancing, bicycling, or jumping rope	−1.515^b	0.396^d	0.117^f	−0.129^h	−0.167^h	0.296^h

Item fit was evaluated using infit and outfit mean square item fit indices (MNSQ), which are based on information-weighted sum of squared standardized residuals and non-weighted sum of squared standardized residuals, respectively. Infit or outfit MNSQ values greater than 1.3 indicate poor item fit
^a Misfit item (item 1) outfit mean square = 1.60
^b Misfit item (item 1) outfit mean square = 1.33
^c Misfit item (item 1) outfit mean square = 1.35
^d Misfit item (item 1) outfit mean square = 1.32
^e Misfit item (item 1) outfit mean square = 1.63
^f Misfit item (item 1) outfit mean square = 1.68
^g Misfit item (item 1) outfit mean square = 1.39
^h Misfit item (item 1) outfit mean square = 1.46

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ISSN: 1479-5868

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