I need to predict the sales of a product P2.
I have access to:
- 7 months of sales history
- 26 months of sales history of another product P1
I assume the sales trends are similar because the products are similar.
The problems are:
- The sales are really impacted by the christmas period.
- The products are not launched in the same month of the year
Question : what is the best way to predict the sales of P2 (orange curve) ?
- A regression (learnt from P1 and applied on P2):
log(sales) = bo +b1*Aging of the product +b2*DecemberFlag ?
Problem: after the Christmas effect, sales never recover the previous trend, i.e the sales stay higher. This is why maybe time series fit more with this problem.
- A time series (learnt from P1 and applied on P2):
How will it manage the seasonality since I don't have a full period for P2? i.e. how can the model predict the sales of P2 in December 2015 since it can't recover the sales in December 2014