How to continue raw data for Forcasting ~ Holts-Winter


New Member
Hi All,

I am new to this forum and i am in need of help regarding the Holt's Winter Method. I've managed to build a forecasting model in excel using the Damped method which works very well.

But due to my lack of experience, I am confused on how to continue the raw data as the forecasting formula requires a data point to work.

My time series is volumes per week per year, historically i was linking the current week back to last years week to repeat some raw data (Bootstrapping?) (linking week 36 2018 to 36 2017 to continue the data), the reason i did this is because of the seasonality. However this is showing some inconsistency with some of my information.

Does anyone know a more accurate way of somehow building this in? Any help would be greatly appreciated