[R-SIG-Finance] Rugarch fitted values lag by 1

[Hannah Linder]

Hello,

I am sorry to post a naive question, but I am struggling to sort this out
on my own. I am fitting the following garch model using the rugarch package:

fit.spec1a[[1]]=ugarchspec(variance.model = list(model = "sGARCH",
                                               garchOrder = c(2,0)),
                         mean.model= list(armaOrder = c(1,0),
                                          include.mean = T),
                         distribution.model = "sstd")

garch[[1]]<- ugarchfit(data=train.set[[2]][,c(1)],spec =
fit.spec1a[[1]],solver="hybrid")


When I examine the fitted values using fitted(garch[[1]]) the values appear
to lag behind the observed values by 1 even though the length of the fitted
series is equal to that of the observed data (See plot below), so I am not
sure if I am using the fitted function incorrectly, or if the fitted values
are truly lagged. Should be using the fitted values from t=2 until t=T
rather than t=1 until t=T for calculations such as RMSE in-sample.

[image: Inline image 2]

Thank-you very much for any help,
Hannah
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