Table 3.

Comparison of the size of convex hulls (CH) derived from questionnaire and CH derived from GPS (n = 23) and prompted recall data (n = 31) collected in Montreal, Canada in 2011

	CH Size (km2)	Ratio of CH sizes: questionnaire to comparison data source
	Median (IQRa)	Median (IQR)
Questionnaire and GPS (n = 23)
Questionnaire activity locations	2. 6 (1.0, 6.3)	N.A
GPS tracks	27.8 (11.7, 186.9)	4.1 (1.2, 41. 5)
GPS activity locations	5.9 (2.1, 58.7)	27.7 (1.9, 74.0)
Questionnaire and prompted recall survey (n = 31)
Questionnaire activity locations	2.6 (1.0, 6.7)	N.A
Prompted recall activity locations	15.5 (6.0, 69.2)	10.8 (3.4, 61.1)

^aIQR: Interquartile range = 25th percentile, 75th percentile.