[EMAIL PROTECTED] (David Reilly) wrote in message news:<[EMAIL PROTECTED]>... > [EMAIL PROTECTED] (jennl) wrote in message news:<[EMAIL PROTECTED]>... > > I am first trying to build a model using regression analysis to > > explain weekly sales, stripped of all exogenous variables (pricing, > > seasonality, etc) and all marketing expenditures > > > You shouldn't strip or pre-filter these exogenous variables as their > impact or weight is most likely inter-dependent with your three > additional variables. Further more there may be lag effects of these > stage 1 variables that you might not be correctly forming. > Additionally there may be Interventions such as Level Shifts or Local > time trends or Holiday Events which might change the Y variable > before,on or after these events. In addition since you are dealing > with time series there may be autoregressive structure in the errors > reflecting omitted variables and one might need to add an ARIMA > component and/or weekly dummies reflecting a deterministic effect for > the week of the year. > > One of our customers Anheuser-Busch ( > http://www.autobox.com/stories.html)is using our software (AUTOBOX) to > perform a similar analysis . They are analyzing sales of 50 SKU's at > 650,000 retail outlets (stores) by day incorporating > price,weather,holidays,events abd special promotions. > > http://www.autobox.com/details.htm report > http://www.autobox.com/actfore.jpg > http://www.autobox.com/intrvent.html > http://www.autobox.com/equation.txt > http://www.autobox.com/verbal.txt > http://www.autobox.com/stat.html > > Specifically they include a 0/1 variable for off/on promotion and > price to customer in order to estimate the impact of promotion and the > impact of price. > > If you wish to discuss this further please feel free to give me a call > at > 215-675-0652 > > Dave Reilly > Automatic Forecasting Systems > http://www.autobox.com > > > > > Regards
Thanks for the insight Dave..I might call you in a little to discuss further.. . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
