https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-do-you-make-the-forecasts-produce-only-positive-numbers-in/m-p/63582#M294 Hello AYDot -<BR /> The way I look at it is as follows: the forecasted values should be derived by the data which you have at hand - which could mean that you are creating negative forecast (if you are facing a negative trend for example). <BR /> <BR /> If you have additional knowledge about the business question at hand (for example: when forecasting sales non-negative numbers might not make a lot of sense) you can go ahead and modify the output of the statistical forecasting engine in a post-process step. <BR /> <BR /> As such you might want to consider the follow approach:<BR /> Start with creating forecasted values using SAS/ETS. If the prediction is negative simply set the values (prediction and confidence interval) to 0 using a data step for example.<BR /> <BR /> Hope this makes sense.<BR /> Regards,<BR /> Udo Thu, 10 Sep 2009 13:33:30 GMT udo_sas 2009-09-10T13:33:30Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-do-you-make-the-forecasts-produce-only-positive-numbers-in/m-p/63581#M293 Hello SAS gurus,<BR /> <BR /> My question is regarding SAS/ETS. Is there a way to force the forecasts to only produce positive numbers? <BR /> <BR /> Also can you select a list of time series models the automatic models selection can choose from in TSFS?<BR /> <BR /> Thanks,<BR /> <BR /> AYDot Wed, 12 Aug 2009 15:10:01 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-do-you-make-the-forecasts-produce-only-positive-numbers-in/m-p/63581#M293 deleted_user 2009-08-12T15:10:01Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-do-you-make-the-forecasts-produce-only-positive-numbers-in/m-p/63582#M294 Hello AYDot -<BR /> The way I look at it is as follows: the forecasted values should be derived by the data which you have at hand - which could mean that you are creating negative forecast (if you are facing a negative trend for example). <BR /> <BR /> If you have additional knowledge about the business question at hand (for example: when forecasting sales non-negative numbers might not make a lot of sense) you can go ahead and modify the output of the statistical forecasting engine in a post-process step. <BR /> <BR /> As such you might want to consider the follow approach:<BR /> Start with creating forecasted values using SAS/ETS. If the prediction is negative simply set the values (prediction and confidence interval) to 0 using a data step for example.<BR /> <BR /> Hope this makes sense.<BR /> Regards,<BR /> Udo Thu, 10 Sep 2009 13:33:30 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/How-do-you-make-the-forecasts-produce-only-positive-numbers-in/m-p/63582#M294 udo_sas 2009-09-10T13:33:30Z