More invitations, or more notice?
Eighteen events, two things you actually control, and one fitted line. Every hundred invitations is worth about 23 attendees and every extra day of notice is worth about 2.4, which turns a calendar argument into arithmetic.
Operations Starter Regression free
After you install, this is the model to open.
What Predicts Turnout?
- 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
What the fit says, with the interval around each lever:
- R-squared
- 0.9670 standard error 10.76 people
- Per 100 invitations
- 20 to 25 attendees
- Per extra day of notice
- 1.7 to 3.1 attendees
- Predictor correlation
- 0.079 two independent levers
At 42 cents an invitation, ten more attendees costs about $18 of list or about four extra days on the calendar, and the calendar is free. Two cautions the output makes visible. The intercept is -36.35, which is nonsense as a prediction and a fitting artefact, so only ask the model about the range it was fitted on: ask it for 5,000 invitations and it will answer, confidently and wrongly. And drop days of notice from the predictors and R-squared falls from 0.967 to 0.859, so lead time is worth about eleven points of explained variation on its own.
The model
Attendance in the first column, invitations sent and days of notice beside it. Both predictors were chosen because they are decisions rather than weather, so both coefficients are levers.
| Events | 18 |
| Predictors | invitations sent, days of notice |
| Invitations range fitted | 700 to 1,400 |
| Notice range fitted | 5 to 29 days |
| Coefficients and intervals | 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
- Packing the best thing first. What does that cost you?Fit the Most Into One Box
- Does the cheapest quote stay cheapest after freight?Which Suppliers Fill the Order Cheapest?
- When does the next unit of stock stop paying?How Much Safety Stock Do We Actually Need?
- How much stock does a longer lead time cost you?When Should We Reorder?
- What does a 95% promise cost, in units?What Stock Level Holds a 95% Service Level?
- Which category did the buying plan get wrong?Is the Product Mix What We Planned For?
Every model like this one, and the method behind them: Statistics in Google Sheets.