dynamic forecast

[raquelopez]

Hello,

My name is Raquel. I am trying to forecast the CPI (ipc in Spanish). I find that the forecasted value of the CPI in 1996m05 by forecasting from 1996m03 to 1996m05 (I understand: from 1 to 3 months ahead) using:

smpl 1991m01 1996m02
equation eq.ls d(log(ipc)-log(ipc(-12))) c ma(12) sma(12)
smpl 1996m03 1996m05
' cpi forecasts from 1 to 3 months ahead
forecast ipcforecast

is different that the forecasted value in 1996m05 by forecasting from 1996m05 to 1996m05 (I guess: forecast 3 month ahead) using:

smpl 1991m01 1996m02
equation eq.ls d(log(ipc)-log(ipc(-12))) c ma(12) sma(12)
smpl 1996m05 1996m05
' cpi forecasts 3 months ahead
forecast ipcforecast

What is the right programming I should use to produce forecasts 3 months ahead?

Thank you in advance for any help you can provide.
Raquel