Use a free SPERT® Excel template.

Estimate. Align. Decide.

Do you need to make an important decision about the future?

Do you need to choose from different investment choices or new product development ideas?

Maybe you just need to align stakeholder expectations on schedule and cost for something you’re building or wanting to build?

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® (2016 / 2019 / 2021 / Microsoft 365 – click here if you’re using an older version of Excel) – 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.  Most Statistical PERT models require only two inputs to provide an infinite number of probabilistic estimates for the future.  Here’s all you do:

  1. Create a 3-point estimate for a bell-shaped uncertainty, like task duration, project expense, or user story count
  2. Render a subjective judgment about how likely the most likely outcome really is
  3. Select any probabilistic planning estimate, or make a risk-based forecast

That’s it!

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 four, production-ready editions of Statistical PERT:  Normal Edition, Beta Edition, Lognormal Edition, and the Bootstrap 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
  • The Lognormal Edition uses Excel’s two lognormal distribution functions, LOGNORM.DIST and LOGNORM.INV
  • The Bootstrap Edition uses statistical bootstrapping, an approach to forecasting using simulation
  • All editions of Statistical PERT are very easy to use

The Normal Edition is easier for a user to customize and has many features suitable for agile teams, whereas the Beta Edition is better suited to modeling a wider range of bell-shaped uncertainties, including uncertainties that are moderately-to-heavily skewed. The Lognormal Edition is the newest edition to the SPERT suite of spreadsheets; it can quickly and easily model many uncertainties that have right-side skewing. The Bootstrap Edition is appropriate for agile teams (Scrum or Kanban) that have at least 6 or 8 historical data points to use in the bootstrap simulation model.

All editions are freely licensed under the GNU General Public License, and all editions are ad-free and macro-free.  Download Statistical PERT® example workbooks or templates now, and try using all editions of Statistical PERT!

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Statistical PERT®, SPERT®, Estimation Made Easy® - © 2015-2024 by William W. Davis, MSPM, PMP. All rights reserved.