Table 2. Characteristics of the sampling design of the first working conditions surveys (WCSs) in Colombia, Argentina, Chile, Central America and Uruguay.

	Colombia	Argentina	Chile	Central America	Uruguay
Population
Situation in the labor market	Employed	Employed	Employed and unemployed, who had any paid job in the last 12 months	Employed at time of the interview or during the previous week for at least one houra	Employed
Employment status	Employee	Employee	Employee, self-employed	Employee, self-employed	Employee, self-employed
Age	–	–	Over 15	Over 18	Over 14
Workplaces characteristics	Registered in the general system of professional risk	Private companies registered in the social security system	–	–	–
Size of the workplace	Two workers or more	Five workers or more	–	–	–
Sectors of economic activity	All sectors	Secondary and tertiary	All sectors	All sectors	All sectors
Formal or informal economy	Formal	Formal	Formal or informal	Formal or informal	Formal or informal
Urban or rural living	–	–	Urban and rural	Urban and rural	Urban and rural
Population size	445 550 workplacesb	3 432 653	7 392 170	12 468 047	1 141 251c
Sampling frame	Database of payments to the occupational hazards fund of 2006	Register of companies from the integrated system of retirement and pensions	Census of Population and Housing 2002	The most recent population census available in each countryd	Area sampling frame from the Census of 2004
Sample size	924 persons in 737 workplaces	7195	9503	12 024 (2004/country)	2057
Type of sampling design	Multistage stratified random sampling	Multistage stratified random sampling and quota sampling	Multistage stratified random sampling	Multistage stratified random sampling	Multistage stratified random sampling and quota sampling
Stratum variables	Regions and economic activity	Urban areas, economic activity, and size of the company	Regions, urban and rural areas	Countries and departments or provinces	Groups of departments and the capital
Selection of the final sampling unit	Workplaces and workers within selected workplaces were selected through random selectione	Workers were selected in the companies through quota sampling by sex and occupation	Compact segment sampling for household selection/one person was selected in the household through random selection	Random walk method for household selection/the next birthday method selection was used to select the person within the household when there was more than one eligible candidate	Random walk method for household selection/one or more persons were selected within the household considering quotas of economic activity

^aIncluding people who were absent from work due to illness, vacation, or other reasons.

^bInformation regarding the size of the target population was not available.

^cAccounts for about 90% of the total working population.

^dGuatemala (2002), El Salvador (2007), Honduras (2001), Nicaragua (2005), Costa Rica (2000), and Panamá (2000).

^eAny worker who was at the workplace at the time of the interview (232 473 workers in total) was included, regardless of the type of contractual relationship.