Table 1. Actual and reported BMI by gender (mean, standard deviation –sd, and Cole’s classification).

	Boys N = 163	Girls N = 140	Difference between genders: P-value
Mean reported height (sd)	179.52 (6.38)	166.12 (6.38)	0.001
Mean actual height (sd)	178.16 (6.62)	164.86 (6.30)	0.001
Mean difference (sd)	−1.36 (3.04)	−1.26 (2.24)	0.755
Mean reported weight (sd)	69.66 (10.56)	57.39 (8.95)	0.001
Mean actual weight (sd)	70.63 (11.75)	59.75 (9.72)	0.001
Mean difference (sd)	1.02 (5.25)	2.36 (3.44)	0.010
Mean reported BMI (sd)	21.56 (2.65)	20.82 (3.29)	0.033
Mean actual BMI (sd)	22.21 (3.10)	22.02 (3.74)	0.636
Mean difference (sd)	0.65 (1.79)	1.21 (1.50)	0.003
Reported BMI classification (%)
Underweight	8.0	16.4	0.030
Normal weight	81.0	75.7
Overweight	11.0	6.4
Obese	0.0	1.4
Actual BMI classification (%)
Underweight	6.1	5.7	0.378
Normal weight	74.9	77.9
Overweight	17.8	12.9
Obese	1.2	3.6
Agreement: reported vs actual BMI
Weighted Kappa	0.56	0.45	–
(95%CI)	(0.42–0.70)	(0.30–0.60)
ICC	0.58	0.56	–
(95%CI)	(0.47–0.67)	(0.44–0.66)
% of correctly classified (%)	83.4	75.0
Body shape perception (%)
(Much) too thin	23.3	7.9	0.001
About the right weight	62.0	57.1
(Much) too fat	14.7	35.0
Objective socioeconomic status (%)
Low	39.3	32.1	0.092
middle	31.3	26.5
high	29.4	41.4
Subjective socioeconomic status (%)
Over average	33.1	35.0	0.998
Around average	60.7	59.3
Below average	6.1	5.7

Reported BMI is based on self-reported weight and height.

Source: Escapad Paris 2010, analytic subsample without non-respondents (n = 303).