Rwanda - Enterprise Survey 2006

The sample for countries participating in the Enterprise Surveys is stratified by industry, firm size, and geographic region.

For stratification by industry, the main manufacturing sectors in each country in terms of value added, number of firms, and contribution to employment are selected. The retail trade sector is also included in all countries as a representative of the services sector, and depending on the size of the economy, the information technology (IT) sector is included. The rest of the universe is included in a residual stratum. In Rwanda, Manufacturing sector included 59 firms, Retail sector - 56 companies and Other sectors (Residual) - 97 businesses.

Size stratification is defined the following way: small establishments (5 to 19 employees), medium establishments (20 to 99 employees), and large establishments (more than 99 employees).

Regional stratification includes the main economic regions in each country. In Rwanda, Butage and Kigali were surveyed.

Through this methodology, estimates for the different stratification levels can be calculated on a separate basis while at the same time inferences can be made for the economy as a whole, weighting individual observations by corresponding sample weights. Sample sizes for each stratification level are defined ensuring a minimum precision level of 7.5% with 95% confidence intervals for estimates with population proportions.

For more technical details on the sampling strategy, please review "Sampling Methodology" in "Technical Documents" folder.