Table 4.

Recruitment methods and rates across 15 International Physical Activity and Environment Study of Adolescents countries

	Australia	Bangladesh	Belgium	Brazil	Czech Republic	Denmark	Hong Kong SAR	India	Israel	Malaysia	New Zealand	Nigeria	Portugal	Spain	USA
Recruitment dates	June 2014–December 2015	December 2015–January 2016	September 2014–December 2015	August 2013–June 2014	Spring 2014–October 2015	Fall 2014 + Spring 2015	October 2012–December 2014	February 2015–June 2016	January 2015–January 2016	October 2015–December 2016	September 2014–June 2015	June 2013–April 2014	September 2014–June 2016	April 2013–October 2015	2009–2011
Age range	12–19	11–18	11–17	11–17	12–18	11–16	11–18	12–17	11–18	12–17	11–18	12–18	11–18	14–18	12–17
Participant identification	Schools	Schools	a. Previous study participants (n=187) b. Schools (n=188)	Address registry	Schools	Schools	Schools	Door to door based on: a. Direct approach b. Staff/volunteer database c. School database	Direct approach, snowball	Schools	Schools	Schools	Schools	Schools	Telephone #s from commercial company
Participant selection method	Recruited from schools selected in neighbourhoods stratified by SES and walkability	Recruited from schools selected in neighbourhoods stratified by SES and walkability	a. Recruited previous study participants living in neighbourhoods stratified by SES and walkability b. Recruited from schools selected in neighbourhoods stratified by SES and walkability	Recruited directly from residential addresses located in census tracts stratified by SES and walkability	Recruited from schools selected in neighbourhoods stratified by SES and walkability	Recruited from schools selected in neighbourhoods stratified by SES and walkability	Recruited students from schools living in preselected neighbourhoods stratified by SES and walkability	Recruited directly from residential addresses located in neighbourhoods stratified by walkability and SES based on expert judgement Used other methods such as school-based databases	Recruited directly from residential addresses located in neighbourhoods selected to vary on SES and walkability	Recruited from schools in areas stratified by SES and walkability	Recruited from schools in areas stratified by SES and walkability	Recruited from schools selected in neighbourhoods stratified by SES and walkability, then random sampling of students from schools.	Recruited from schools selected in areas stratified by SES and walkability, then random sampling of students from schools.	Recruited from schools in areas stratified by SES and walkability	Recruited directly from randomly sampled residential addresses located in neighbourhoods stratified on SES and walkability, many NH used all available records
School schedules	Monday–Friday	Saturday–Thursday for most. Morning and afternoon sessions.	Monday–Friday	Morning, afternoon, and/or evening sessions. Some classes on Saturdays	Monday–Friday	Monday–Friday	Monday–Friday	Monday–Friday with classes on some Saturdays and Sundays also.	Sunday–Thursday or Friday. Variable schedules.	Monday–Friday Morning and afternoon sessions.	Monday–Friday	Monday–Friday	Monday–Friday Some students attended school twice a day	Monday–Friday schedule. Some students attended school twice a day	Monday–Friday
Incentives	None	None	None	None	None	Drawing for bowling or go-carts with friends (2014), or play equipment for class (2015)	HK$50 for survey; HK$50 for accelerometry	Rs. 750–1000 (US$12–15) gift vouchers	150 Israeli shekels per individual	RM 30 MYR (in form of T-shirt /meal)	Drawing to receive US$100 shopping voucher/US$200 voucher for parents	Gift (Souvenirs) worth US$10	None	None	US$40
Participation rate	36.3%* 528 consents/1454 presented recruitment packet	Unable to calculate as the number of invited participants is unknown	42.3%  Previous study method: 187 consents/ 442 eligible contacts  School recruitment method: unable to calculate as number of invited participants is unknown	61.7% 590 enrolled/956 eligible and accessible contact	89.7% 758 consents/845 invited	16.7% 286 consents/1716 invited	68% 1363 consents/2002 invited	11%; 67%  Staff database method:  11 agreed/100 approached  School references method: 113 agreed/ 170 approached  School recruitment method: unable to calculate as number of invited participants is unknown	Unable to calculate as the number of invited participants is unknown	73.3% 440 consents/600 distributed	12.8% 752 consents/5883 invited	42.9% 278 enrolled/ 648 invited	35.7% 240 consents/673 invited	80% Schools chose classrooms. Within classrooms, recruitment rate was 80% on average.	39.6% 1038 enrolled/2619 eligible contacts

*This excludes one visit to a school where the recruitment sheet was not available.

SES, socioeconomic status.