www.ijbnpa.org

Table 1
Comparative summary of time use surveys constituting the AHTUS with a focus on walking behaviours
Year(s)	1965–1966	1975–1976	1985	1992–1994	2003

Name	Americans' Use of Time (part of the Multinational Comparative Time-Budget Research Project)	Time Use in Economic and Social Accounts	American's Use of Time	US. Environmental Protection Agency National Human Activity Pattern Survey	American Time Use Survey
Organization	Survey Research Center, University of Michigan	Survey Research Center, University of Michigan	Survey Research Center, University of Maryland	Survey Research Center, University of Maryland	United States Bureau of Labor Statistics and United States Census Bureau
Sample	Jackson 759 diaries National 1262 diaries	4584 diaries (main respondent only)	2636 diaries	7514 diaries	19,663 diaries
Age range	19–65 (some up to 69)	18+	12+ (18+ in AHTUS)	0+ (18+ in AHTUS)	15+ (18+ in AHTUS)
Response rate	82% Jackson, 74% National	72% first wave, 45% did all 4 waves	55% overall, 51% for mail back sample	63%	58%
Collection method	Self-completion with guidance from interviewer	Self-report waves 1&4, phone waves 2 &3*	3 samples: CATI, self-completion, personal interview (only self-completed in AHTUS)	CATI	CATI
Walking variables captured	Any walking Walking for exercise	Any walking Walking for exercise	Any walking Walking for exercise Walking for transport Walking the dog	Any walking Walking for transport Walking the dog (Walking for exercise was captured under either Walking for Transport or, for this year only, Sports &Exercise)	Any walking Walking for exercise Walking for transport Walking the dog
Other PA variables	Sports & exercise Total PA*	Sports & exercise Total PA*	Sports & exercise Total PA*	Sports & exercise Total PA***	Sports & exercise Total PA*

Adapted from Fisher et al.[24] for these analyses we randomly sampled one wave for each participant of the 1975 survey; walking for exercise not included; **all walking and sports & exercise considered, no double-counting
Tudor-Locke et al. International Journal of Behavioral Nutrition and Physical Activity 2007 4:45 doi:10.1186/1479-5868-4-45

Table 1