Matrix Balancing by the Ordinary RAS MethodΒΆ

In work with input-output analysis, one frequently needs to balance a table to known row and column totals. Three methods of scaling are offered in G7: ordinary RAS, proportional scaling RAS (psras), and right-direction RAS (rdras). In additional, outside information may be imposed using the “precondition” features described below.

The RAS commands are:

ras|psras|rdras [<-f|c>] <matrix>[(r rgroup)][(c cgroup)]<rowctrl><colctrl> [yr][r|c][-maxiter][-precon] [-tolerance]

where:

-f|c:specifies the flow (default) or the coefficient mode,
ras|psras|rdras:
 specifies the method of scaling to be used,
matrix:is the name of the matrix whose elements are to be balanced,
(r rgroup):
(c cgroup):are options that determine which rows and columns are included,
rowctrl:
colctrl:are vectors that contain the row and column totals,
yr:optionally specifies the year for which the matrix is to be balanced. If a year is not specified, the matrix is balanced over the period specified by the current fdates.
r|c:optionally specifies whether the sum of the row totals or the sum of the column totals controls the calculations if the two are not the same.
-maxiter:optionally determines maximum number of iterations. The default is 100.
-precon:optionally specifies that name of a file containing the preconditions that are to be imposed.
-tolerance:optionally specifies the tolerance for the convergence test. The default value is 0.000002.

If one or more of row and/or column totals are questionable, the matrix still may be balanced by a special use of proportional scaling RAS, which is explained in Balancing Matrices with Uncertain Totals.

Related Topics: coef, flow, psras, rdras

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