Data Estimator is a tool that helps answer questions about uncertain quantities, eg. "What will our company's sales be next year?"

It is designed to be used as part of an interview process, where your expert judgments are drawn out and quantified.

You will be asked several questions, using "probability wheels" to visualise uncertain quantities.

Once the data has been assessed, you will be able to see and export the resulting probability distribution; eg. the result could be "there is a 60% chance this market will more than double in five years, a 20% chance it will more than treble, but a 10% chance it will shrink."

You can leave all the fields blank to try it out.

Thank you for your time today. You'll find below a chart of the cumulative probability distribution we have assessed. The blue curve shows the points you chose, connected with straight lines. The grey curve is the Weibull distribution which best fits those points.

Cumulative Probability Distribution


Probability Density


Calculating best fit Weibull distribution...

The best fit Weibull distribution has shape parameter , scale , and location .

Statistic Piecewise Linear* Weibull Fit**

Decision Tree Nodes (Piecewise Linear)*

Decision Tree Nodes (Weibull Fit)**

Probability Piecewise Linear* Weibull Fit**
* Values interpolated using piecewise linear interpolation (the blue curve above)
** Values interpolated using the Weibull cumulative distribution which minimises the squared deviation from the assessed points (the grey curve above)