If argument method
is 'DW92' the method of Diewert and
Wales (1992) is applied. They predetermine the weights by
$$ \theta_{i} = \frac{
\displaystyle \left | \overline{x}_{i} \right| p_{i}^{0} }{
\displaystyle \sum_{i=1}^{n} \left| \overline{x}_{i} \right| p_{i}^{0}}$$
Defining the scaled netput quantities as
\(\widetilde{x}_{i}^{t} = x_{i}^{t}\cdot p_{i}^{0}\)
we get following formula:
$$ \theta_{i} = \frac{
\displaystyle \left| \overline{ \widetilde{ x } }_{i} \right|}{
\displaystyle \sum_{i=1}^{n} \left| \overline{ \widetilde{ x } }_{i} \right|}$$
The prices are scaled that they are unity in the base period or - if there
is more than one base period - that the
means of the prices over the base periods are unity.
The argument base
can be either
(a) a single number: the row number of the base prices,
(b) a vector indicating several observations: The means of these
observations are used as base prices,
(c) a logical vector with the same length as the data
: The
means of the observations indicated as 'TRUE' are used as base prices, or
(d) NULL
: prices are not scaled.