https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961784#M4966 Dear Expert,<BR /><BR />Thanks a lot for your advice!<BR /><BR />Tony Thu, 13 Mar 2025 13:12:23 GMT Tony_Chan 2025-03-13T13:12:23Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961748#M4964 <P>Dear Experts,</P><P>&nbsp;</P><P>I would like to seek your help in guiding me in backcasting those lost observations due to differencing to achieve stationarity of a time series. The ARIMA procedure does provide an option called "back=" in the forecast statement. However, it cannot help backcast any lost observations.&nbsp;Please advise.</P><P>&nbsp;</P><P>Thank you very much!</P><P>&nbsp;</P><P>Tony</P> Thu, 13 Mar 2025 02:30:54 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961748#M4964 Tony_Chan 2025-03-13T02:30:54Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961777#M4965 <P>Dear&nbsp;<a href="https://communities.sas.com/t5/user/viewprofilepage/user-id/438016">@Tony_Chan</a>&nbsp;</P> <P>For this issue, you might be best served by contacting Technical Support and requesting SAS Content Assessment Tool support.&nbsp; Here is a link for your convenience:&nbsp;<A href="https://support.sas.com/en/technical-support.html#contact" target="_blank">https://support.sas.com/en/technical-support.html#contact</A>&nbsp;</P> <P>Thank you for using SAS!</P> Thu, 13 Mar 2025 11:46:19 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961777#M4965 Sa_S 2025-03-13T11:46:19Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961784#M4966 Dear Expert,<BR /><BR />Thanks a lot for your advice!<BR /><BR />Tony Thu, 13 Mar 2025 13:12:23 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961784#M4966 Tony_Chan 2025-03-13T13:12:23Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961796#M4967 <P><SPAN>Thank you for the post- we are responding in your TS case. Thanks, and have a great day!</SPAN></P> Thu, 13 Mar 2025 15:31:14 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-to-backcast-lost-observations-due-to-regular-seasonal/m-p/961796#M4967 Sa_S 2025-03-13T15:31:14Z