Table 2.
Least-squares means (± standard errors) from the general linear model repeated-measures analysis conducted for each of the five outcome measures (calculated for each day of a child’s three days of observation/interview combinations)
| Number of items observed eaten a, b | Number of items reported eaten a,c | Omission rate (in %) a,d | Intrusion rate (in %) a,e | Total inaccuracy (in servings) a,f,g | ||
|---|---|---|---|---|---|---|
| BMI Category h x Trial: | i | j | k | |||
| Healthy weight | Trial 1 | 8.3 ± 0.3 | 6.8 ± 0.3 | 56% ± 3% | 47% ± 3% | 7.5 ± 0.4 |
| Trial 2 | 8.1 ± 0.3 | 7.0 ± 0.3 | 48% ± 4% | 39% ± 4% | 6.7 ± 0.5 | |
| Trial 3 | 8.4 ± 0.2 | 7.2 ± 0.3 | 42% ± 3% | 33% ± 3% | 6.2 ± 0.4 | |
| At risk of overweight | Trial 1 | 10.0 ± 0.5 | 6.8 ± 0.6 | 64% ± 6% | 49% ± 6% | 9.4 ± 0.8 |
| Trial 2 | 8.5 ± 0.5 | 6.7 ± 0.6 | 54% ± 7% | 40% ± 7% | 7.1 ± 1.0 | |
| Trial 3 | 8.6 ± 0.4 | 6.5 ± 0.6 | 57% ± 6% | 43% ± 7% | 7.6 ± 0.8 | |
| Overweight | Trial 1 | 9.6 ± 0.5 | 7.3 ± 0.6 | 47% ± 6% | 30% ± 6% | 6.9 ± 0.8 |
| Trial 2 | 9.5 ± 0.5 | 7.1 ± 0.6 | 54% ± 6% | 36% ± 7% | 7.4 ± 0.9 | |
| Trial 3 | 8.7 ± 0.4 | 6.2 ± 0.6 | 57% ± 6% | 37% ± 6% | 6.3 ± 0.8 | |
| Trial: | j | k | l | |||
| Trial 1 | 9.3 ± 0.2 | 7.0 ± 0.3 | 56% ± 3% | 42% ± 3% | 7.9 ± 0.4 | |
| Trial 2 | 8.7 ± 0.3 | 6.9 ± 0.3 | 52% ± 3% | 38% ± 3% | 7.1 ± 0.5 | |
| Trial 3 | 8.6 ± 0.2 | 6.6 ± 0.3 | 52% ± 3% | 38% ± 3% | 6.7 ± 0.4 | |
| BMI Category: | i | |||||
| Healthy weight | 8.2 ± 0.2 | 7.0 ± 0.2 | 49% ± 2% | 40% ± 2% | 6.8 ± 0.4 | |
| At risk of overweight | 9.0 ± 0.3 | 6.7 ± 0.5 | 58% ± 4% | 44% ± 4% | 8.0 ± 0.7 | |
| Overweight | 9.3 ± 0.3 | 6.9 ± 0.4 | 53% ± 4% | 34% ± 4% | 6.9 ± 0.6 | |
| Sex: | l | |||||
| Girl | 8.6 ± 0.2 | 6.6 ± 0.3 | 53% ± 3% | 38% ± 3% | 6.6 ± 0.4 | |
| Boy | 9.0 ± 0.2 | 7.1 ± 0.3 | 54% ± 3% | 41% ± 3% | 7.9 ± 0.5 |
A weight was assigned to each match (an item observed eaten and reported eaten), omission (an item observed eaten but not reported eaten), and intrusion (an item reported eaten but not observed eaten) according to importance by meal component with combination entrée (e.g., hamburger, sausage biscuit) = 2, condiment (e.g., ketchup) = 0.33, and other meal components (e.g., chicken, milk, green beans, roll, pear, cake) = 1. Thus, reporting errors for combination entrées counted more than reporting errors for condiments and remaining meal components.
Number of items observed eaten = sum of weighted number of items observed eaten at school breakfast and school lunch, per trial per child.
Number of items reported eaten = sum of weighted number of items reported eaten for school breakfast and school lunch, per trial per child. For the weighted number of items reported eaten, no significant effects were found for the tests of within-subjects contrasts (all P values > 0.135), or for the tests of between-subjects effects (all P values > 0.247).
For school breakfast and school lunch for each trial for each child, omission rate = (sum of weighted omissions / [sum of weighted omissions + sum of weighted matches]) * 100. Omission rates may range from 0% (i.e., no omissions) to 100% (i.e., no matches: no items observed eaten were reported eaten).
For school breakfast and school lunch for each trial for each child, intrusion rate = (sum of weighted intrusions / [sum of weighted intrusions + sum of weighted matches]) * 100. The intrusion rate was undefined if a child was observed to eat something but reported eating nothing. Defined values for intrusion rates may range from 0% (i.e., no intrusions) to 100% (i.e., all reported items were intrusions).
For school breakfast and school lunch for each trial for each child, total inaccuracy = (absolute difference between amounts reported and observed for each match * weight) + (amount of each omission * weight) + (amount of each intrusion * weight) summed over all items at observed meals on an individual day for each child. A total inaccuracy score of zero indicates a perfect recall relative to observation.
Amounts eaten were observed, reported, and scored in servings as none (0.0), taste (0.1), little bit (0.25), half (0.50), most (0.75), all (1.0), or the actual number of servings if >1 serving (e.g., 2).
According to the CDC sex-specific BMI-for-age growth charts and categories [40,41], children with BMI-for-age ≥ 5th percentile and <85th percentile were classified as healthy weight, children with BMI-for-age ≥ 85th percentile and <95th percentile were classified as at risk of overweight, and children with BMI-for-age ≥ 95th percentile were classified as overweight.
For the weighted number of items observed eaten, there was a marginally significant BMI category x trial interaction (P = 0.079; F2,72 = 2.6). In addition, BMI category was significant for the tests of between-subjects effects (P = 0.015; F2,72 = 4.5).
For omission rate, there was a significant effect of trial (P = 0.006; F1,72 = 8.1) and a significant BMI category x trial interaction (P = 0.028; F2,72 = 3.8).
For intrusion rate, there was a significant effect of trial (P = 0.025; F1,72 = 5.3) and a marginally significant BMI category x trial interaction (P = 0.083; F2,72 = 2.6).
For total inaccuracy, there was a marginally significant effect of trial (P = 0.076; F1,72= 3.2). In addition, sex was significant for the tests of between-subjects effects (P = 0.049; F1,72 = 4.0).