https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49822#M240 Udo, thanks a lot !<BR /> <BR /> I'll try it. Wed, 21 Jul 2010 19:41:03 GMT Werg 2010-07-21T19:41:03Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49818#M236 Hello everyone !<BR /> <BR /> It's my very first time in this forum. <BR /> I'm trying use 2 prices as an exogenous in a ARIMAX model. But I need to define a restriction in the first price (because doesn't make sense increase the price and the sales increase to), and leave the second price (parameter) free.<BR /> I know it's possible apply a restriction (positive or negative) on input, but i don't know if it's possible define different rules for different inputs. Thu, 15 Jul 2010 03:26:23 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49818#M236 Werg 2010-07-15T03:26:23Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49819#M237 Hello -<BR /> Not sure if this makes sense, but it might be worthwhile to check out the MODEL procedure of SAS/ETS - see: <A href="http://support.sas.com/documentation/cdl/en/etsug/60372/HTML/default/etsug_model_sect048.htm" target="_blank">http://support.sas.com/documentation/cdl/en/etsug/60372/HTML/default/etsug_model_sect048.htm</A><BR /> Thanks,<BR /> Udo Tue, 20 Jul 2010 09:20:18 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49819#M237 udo_sas 2010-07-20T09:20:18Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49820#M238 Hello Udo,<BR /> <BR /> it's something like that, but I thought I could use the proc hpfdiagnose. In the Input Statement is possible define REQUIRED=MAYBE(NEGATIVE), but I don't need restrict all the variable inputs, but only the price.<BR /> <BR /> Thanks ! Wed, 21 Jul 2010 13:19:42 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49820#M238 Werg 2010-07-21T13:19:42Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49821#M239 Hi -<BR /> Have you considered using multiple INPUT statements?<BR /> HPFDIAG allows for that - so you would be able to specify different REQUIRED= statements for each of the variables if needed.<BR /> Thanks,<BR /> Udo Wed, 21 Jul 2010 15:28:03 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49821#M239 udo_sas 2010-07-21T15:28:03Z https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49822#M240 Udo, thanks a lot !<BR /> <BR /> I'll try it. Wed, 21 Jul 2010 19:41:03 GMT https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/Price-elasticity-and-parameter-restrictions/m-p/49822#M240 Werg 2010-07-21T19:41:03Z