Hi,

I am doing ex-ante out of sample forecasting for rail freight. Based on the results of the ADF Test and AIC, I am predicting the freight value for rail for years 2020-2030 based on past values from 2007-2019. However, whenever, I use dynamic in predict, I get the error that the option dynamic is not allowed in the command.

I have run the following commands:
gen t=_n
tsset t

gen RailFreightDiff = d.RailFreight
dfuller RailFreightDiff, drift regress lags(1)
varsoc RailFreightDiff

set obs 24; I tried set obs '=_N=11' command but got the error, observation number out of range.

gen RailLag1 = RailFreightDiff[_n-1]
gen RailLag2 = RailFreightDiff[_n-2]
reg RailFreightDiff RailLag1 RailLag2, r
predict Rail, dynamic{24}


The sample of the data set using dataex:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input int year long railfreight float t long RailFreightDiff float(RailLag1 RailLag2)
2007 5215858  1       .       .       .
2008 5517042  2  301185       .       .
2009 6001461  3  484419  301185       .
2010 6258547  4  257086  484419  301185
2011 6676755  5  418208  257086  484419
2012 6492100  6 -184655  418208  257086
2013 6656881  7  164782 -184655  418208
2014 6812517  8  155636  164782 -184655
2015 6542970  9 -269548  155636  164782
2016 6205502 10 -337468 -269548  155636
2017 6934109 11  728608 -337468 -269548
2018 7389954 12  455845  728608 -337468
2019 7081283 13 -308672  455845  728608
end