Excel is an amazing tool that allows users to organize data in spreadsheets and manipulate it using a large selection of functions. However, many WFM departments also use it as a forecasting software for their time series. There are reasons why this is not a wise choice. We will elaborate on these reasons. Excel is not a database Using Excel for forecasting indirectly assumes that spreadsheets are used as database; asking that duty from Excel is one of the most notorious reasons for business inefficiencies. In fact, once your data grows, your spreadsheet grows too and becomes very slow [...]

Call center forecasting is a fascinating field where science and business intersect to create stimulating challenges. However, business requests sometimes contradict scientific reasoning such as using external variables to predict call volumes. As a forecasting specialist I often receive an Excel sheet from the sales department containing future demand forecasts and I am asked to use this information to provide call volume forecasts for the coming weeks. Considering future demand to predict future calls seems, at first glance, entirely reasonable; after all, if sales increase, more customers will try to contact. The problem is that we want to predict [...]

I am lucky not to be a forecaster… because they really have a difficult job. They have to differentiate between the effects of many factors, such as day-of-the-week, week-of-the-year, long-term trend, marketing events - without being able to tell exactly what the effect of each factor is. The reason for this is twofold: factors change over time, depending on the time of the year, changes in the call center or the company’s business, etc. But also because everything is obscured by a layer of noise. Think about it: if you forecast 30 calls in half an hour, then 30 customers [...]