Do you need to quickly create a reliable, confident, cost estimate or revenue projection? Do you need a release date forecast for an agile-developed product? How about estimating a project’s task duration, or creating a whole project forecast? If so, then download Statistical PERT now – it’s free!
If you can render a subjective judgment about any bell-shaped uncertainty – and you have access to Microsoft Excel® (2010 / 2013 / 2016 / 2019 / Office 365) – you can use the Statistical Program Evaluation and Review Technique (Statistical PERT® , or just SPERT®). Statistical PERT lets anyone create a probabilistic estimate or forecast using the built-in functions of Microsoft Excel. Statistical PERT requires only two inputs to provide an infinite number of probabilistic estimates for the future. Here’s all you do:
- Create a 3-point estimate for a bell-shaped uncertainty, like task duration, project expense, or user story count
- Render a subjective judgment about how likely the most likely outcome really is
- Select any probabilistic planning estimate, or make a risk-based forecast
Choose a cost estimate or task duration that has a very low probability of being exceeded — or cut that estimate and assume more risk that your budget or schedule won’t be enough. Forecast an agile product’s likely release date, or what features will likely be included by a hard delivery date. Forecast revenue. Estimate entire projects and create project schedules with timelines that perfectly fit your risk tolerance. Play what-if scenarios to see how choosing different inputs into the model will affect the resulting probabilities.
You make the final call! Using Statistical PERT, you now have a variety of probabilistic estimates at your fingertips to make the best choice.
Statistical PERT templates and example workbooks are Excel files that use standard, built-in Excel functions to forecast the future. There is nothing to buy, nothing to install, no macros, no advertising, no adware, and no registration required!
There are two editions of Statistical PERT: Normal Edition and Beta Edition.
- The Normal Edition uses Excel’s two normal distribution functions, NORM.DIST and NORM.INV
- The Beta Edition uses Excel’s two beta distribution functions, BETA.DIST and BETA.INV
- Both editions of Statistical PERT are very easy to use
The Normal Edition is easier for a user to customize, whereas the Beta Edition is better suited to modeling a wider range of bell-shaped uncertainties, including uncertainties that are moderately-to-heavily skewed. Both editions are freely licensed under the GNU General Public License, and both editions are ad-free and macro-free. Download Statistical PERT example workbooks or templates now, and try using both editions of Statistical PERT!