Table 8.

Sensitivity, specificity and positive predictive value of self-reported data and correction equations for weight status

Grade	Weight Status	Sensitivity			Specificity			Positive Predictive Value
		Girls	Boys	All	Girls	Boys	All	Girls	Boys	All
Self-Reported
8th	Overweight	58.2%	62.7%	60.5%	91.2%	87.5%	89.2%	60.1%	51.6%	55.3%
	Obese	66.8%	73.6%	70.8%	97.7%	96.4%	97.0%	84.0%	83.0%	83.4%
	Overweight/Obese	77.2%	84.6%	81.3%	93.9%	88.5%	91.1%	86.7%	81.2%	83.4%
11th	Overweight	64.1%	60.4%	62.0%	95.2%	92.7%	93.9%	71.1%	63.8%	66.9%
	Obese	76.3%	85.0%	81.9%	98.9%	97.5%	98.1%	89.8%	88.7%	89.1%
	Overweight/Obese	81.4%	84.2%	83.1%	97.5%	93.6%	95.6%	92.5%	88.4%	89.9%
Correction Equations
8th	Overweight	67.4%	62.5%	64.8%	86.8%	86.9%	86.9%	54.0%	50.2%	52.1%
	Obese	73.4%	80.2%	77.4%	97.1%	96.5%	96.8%	82.0%	84.7%	83.7%
	Overweight/Obese	86.0%	86.3%	86.1%	88.2%	86.9%	87.5%	78.9%	79.4%	79.2%
11th	Overweight	72.0%	69.6%	70.7%	91.2%	90.6%	90.9%	59.9%	61.2%	60.6%
	Obese	82.4%	85.5%	84.4%	99.0%	97.2%	98.1%	91.4%	87.8%	89.0%
	Overweight/Obese	85.9%	89.7%	88.2%	92.0%	91.1%	91.5%	80.1%	85.2%	83.2%

Using the U.S. Centers for Disease Control and Prevention (CDC) sex and age BMI growth charts, we classified students into underweight/normal (<85th percentile), overweight (≥85th percentile to <95th percentile) and obese (≥95th percentile) weight status categories

Sensitivity: proportion of the weight status category correctly classified by self-reported measurements in that weight status category

Specificity: proportion of students who were not in the weigh status category as correctly classified as not in that weight status category by self-reported measurements.

Positive predictive value: proportion of students identified by self-reported measures with a particular weight status that are truly in such particular weight status