Hi, A naive forecast model can be represented as an ARIMA(0,1, 0) without a constant term. When I try this in Gretl, I get an error message: Command has insufficient arguments. How can I do a naive forecast with the ARIMA? I need to show my students how this is done. Thanks, Walt ________________________ Walter R. Paczkowski, Ph.D. Chief Data Scientist Data Analytics Corp. 44 Hamilton Lane Plainsboro, NJ 08536 ________________________ (V) 609-936-8999 (F) 609-936-3733 walt(a)dataanalyticscorp.com www.dataanalyticscorp.com _____________________________________________________