Definition: Bottom-up methods

Category: Regional accounts and indicators

The bottom-up methods or ascending method of estimating a regional aggregate involves collecting data at local unit KAU, and ascending by addition until the regional value of the aggregate is established. The method is named bottom-up because the elements for calculating the aggregate are directly collected at this local KAU level.
A pseudo-bottom-up approach can be followed where data for local KAU are not available. Data for local KAU can be estimated from enterprise, KAU or local unit data, using one of the methods in section 3.2. The estimates can then be aggregated to obtain regional totals just as in a purely bottom-up approach. Many enterprises have only one local KAU and this method only requires estimation for multi-regional and heterogeneous enterprises.