RAS Technique

Definition

RAS Technique or RAS Procedure or RAS algorithm was originally introduced to update IO-tables in situations in which only limited survey data are available for the projection year.

Method used in the preparation of updated I-O accounts that are based on partial survey information. The technique applies row and column balancing factors iteratively until the adjusted matrix (the transactions table) satisfies the row and column totals (commodity and industry output). The technique converges to a solution resulting in a balanced I-O matrix.

Procedure

Assume that an input-output direct coefficients table for an n-sector economy for a given year in the past (in what follows, designate this as year “0”) and that we like to update those coefficients to a more recent year (for example, the current year, which we will designate year “1”).

The RAS technique generates an estimate of these coefficients from 3n pieces of information for the year of interest (year 1). These are: (1) total gross outputs, xj (which are also needed with survey-based transactions information); (2) total interindustry