ARIMA model forecast for nonstationary data

hmhsing
hmhsing Altair Community Member
edited November 5 in Community Q&A
Hello,

I am using ARIMA(3,1,3) to forecast the S&P 500 close index. The (p,d,q) are determined from Optimize Parameters (Grid). However, the forecast values look strange to me (way too big). If I change to ARIMA(3,0,3) it turns out fine. Does this mean when d is not zero I need to do some other way to forecast?   





The rmp and data files are attached. Thanks for anyone's help! 

Tagged: