Sample size
The sample size was approximately 2,500 households over the whole national territory of Bulgaria, excluding replaced households.
General Census information - Last done in 1992
In Bulgaria there were approximately 40,000 Statistical Sectors (SS). Each one contained approximately 80 households, giving a total of 2.9 million households. The average household size was 3 and the total population was approximately 9 million (8,459,763 at the last count in December 1993).
Sample Selection
A fixed number of households (5) was collected in each SS. The number of SS that were selected, were 500 (5*500=2,500). Each cluster was selected with probability proportional to the number of households in each cluster from a subsample of 4,000 available representative clusters.
The general sample methodology had been designed to insure that all the households of different size and in all regions and town had the same probability to be selected. The actual sampling of the households were done in two stages: a) In the first stage the SS were Selected with Probability Proportional to the Size. The listing had been organized in the following order: (i) the list of the 28 regions, (ii) Cities, towns and villages; (iii) each city and town was listed by size; b) In the second stage the households interviewed were selected with Equal Probability, provided that they had been listed according to their size (all households of one person first, all the households of two people second and so on).
