When the level shifts, how fast does your forecast follow?
A step change, the shape a price change or a new stockist leaves behind, is where long averages fail: they keep doubting. Exponential smoothing weights recent points more, and one knob sets how much.
Work Starter Forecasting free
After you install, this is the model to open.
A Forecast That Trusts Recent Weeks
- In your spreadsheet, click the Sortia icon in the strip of icons down the right-hand edge. No strip? Click the arrow at the bottom-right to open it. You can also use Extensions, then Sortia, then Open Sortia.
- Click Start from a template and put that name in the search box.
- Pick the card with that name and click Load this template. It arrives on a new tab with real numbers already in it.
The answer
Watch the forecast column absorb the step:
- Week after the jump
- 229.5 forecast
- Two weeks after
- 241.0 forecast
- Next week
- 241.1 your number
The forecast absorbs the new level in about two weeks, while a five-week average would still be splitting the difference. The damping knob is the whole art: near 0 chases every wiggle including the noise, near 1 barely updates. Series with real trend or seasonality deserve Holt-Winters; this tool is for levels that shift.
The model
Ten weeks of sales hovering around 203, then stepping up to the 240s in week six. Damping 0.3 means a smoothing constant of 0.7: each forecast is 70% last week and 30% everything older.
| Weeks 1-5 | around 203 |
| Weeks 6-10 | around 243 |
| Damping factor | 0.3 |
| Forecast column | calculated |
Once it is in your sheet
- The model arrives with real numbers in it and runs as it stands, so you can press the button first and understand it second.
- Change the numbers to yours. The sheet marks which cells are inputs and which hold formulas, and most labels carry a note explaining the row.
- Press the run button at the bottom of the panel. It is labeled for the tool you are in, and the result lands on its own tab, with a written reading of it beside the figures.
Never used Google Sheets? Start here goes the whole way, in seven steps, and assumes nothing.
Next question
- What happens to the plan when reps leave?Will the Sales Team Make the Number?
- What is a pilot actually worth before you commit?Pilot First, or Go Big?
- What does each of the three budgets actually produce?Which of Three Budgets Should the Practice Plan On?
- Is the biggest engagement worth the two it blocks?Which Engagements Should We Take?
- Is filling every billable hour the wrong plan?Where Should My Own Week Go?
- Is 32 hours a week a target or a wish?What Does a Typical Billable Week Look Like?
Every model like this one, and the method behind them: Forecasting in Google Sheets.