(1989), "Two Exact, Non-Arbitrary and General
Methods of Decomposing Temporal Change", *Economics Letters*,
(**30**), pp. 151-156.

A common goal in economics is to attribute changes in a variable
Y between two points in time to various causes, when the only
information available is an equation expressing Y as a matrix
product of several variables, and the values of all variables
at the two dates. Past methods of decomposing temporal changes
into various components are found to suffer from one or more of
the following problems: they can be *arbitrary* due to the
uncertainty concerning whether to expand about the initial or
final time period, *inexact* due to a residual term, and
*specific* to cases in which the variable is a product of
two matrices. This paper presents two decomposition methods which
overcome all three shortcomings of earlier methods.