The Forecast Is Always Wrong
I've never seen a forecast that was exactly right. The question isn't whether you'll be wrong — you will be. The question is whether you're wrong in a predictable, manageable way.
A good forecast doesn't predict the future. It gives you a range of likely outcomes and helps you understand which variables drive the most uncertainty.
The Three Sources of Forecast Error
1. Pattern errors. Your model doesn't capture the right seasonality. You're using daily patterns when you need hourly ones. You're using last year's data when the business has changed.
2. Event errors. You didn't account for a campaign, a product launch, a regulatory change, or a competitor's action. These are knowable in advance — but only if you have a process for capturing them.
3. Structural errors. Your model assumes the future looks like the past. Sometimes it doesn't. New channels, new customer behaviors, new products — these break historical models.
What Good Forecasting Looks Like
It's collaborative. The WFM team doesn't forecast in isolation — they work with marketing, operations, and product teams to capture known events. It's iterative. You review your forecast accuracy weekly and adjust your model. And it's honest about uncertainty — you give ranges, not point estimates.
A forecast is a tool for planning, not a promise about the future.