TheilU(a, p, type = c(2, 1), na.rm = FALSE)
NA
values should be stripped before the computation proceeds. If set to TRUE
complete cases of cbind(x, y)
will be used. Defaults to FALSE
.type = 1
is taken from Theil (1958, pp. 31-42). The argument a
represents the actual observations and p
the corresponding predictions. He left it open whether a
and p
should be used as absolute values or as observed and predicted changes.
Theil (1966, chapter 2) proposed U type = 2
as a measure of forecast quality: "...where $A_i$ and $P_i$ stand for a pair of predicted and observed changes. ..."
As $U_1$ has some serious disadvantages (see Bliemel 1973) it is recommended to use $U_2$.Gini
TheilU(1:10, 2:11, type=1)
TheilU(1:10, 2:11, type=2)
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