The 2001 Bulgaria Integrated Household Survey was conducted by BBSS Gallup International under the supervision of the World Bank. Because of the expected excessive level of attrition due to the large time lag from the last survey and the massive internal and external migration since 1997, for the purpose of this survey it was decided to draw a new cross-section of households. Using the same stratified two-stage cluster design adopted in 1995, a similar nationally-representative sample was drawn by the National Statistical Institute (NSI) from the pre-census listing of the 2001 Population Census.
The main objective of the survey was to provide comparable poverty figures with the previous studies, the questionnaire used is virtually identical to the one used in the previous surveys and when changes were introduced particular attention was paid to maintain consistency with the previous questionnaires.