What is the best distribution to use for schedule duration?

General discussion and questions about project risk management and risk analysis software RiskyProject. Includes discussion on how to perform efficient project risk analysis using our software.

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RiskUser
Posts: 6
Joined: Fri Jun 11, 2010 5:11 pm

What is the best distribution to use for schedule duration?

Post by RiskUser » Mon Aug 31, 2015 3:03 pm

When you add low and high durations to an activity, what type of distribution is the best?
thanks

Intaver Support
Posts: 832
Joined: Wed Nov 09, 2005 9:55 am

What is the best distribution to use for schedule duration

Post by Intaver Support » Mon Aug 31, 2015 4:39 pm

In reality, there is no “Best” distribution to use for schedule or cost risk analysis. The statistical distribution for any parameter (cost, duration etc) should be the one that best fits your data.
If this data does exist for particular type of activities, then you can select the distribution which best fits your data or you can create a custom distribution. However, in reality, most of our users do not have this data available for the type of activity. In these cases, we suggest using Triangular statistical distribution as the default. Triangular distributions only require that you provide Best Case, Most Likely, and Worst Case values without requiring any additional parameters. In our experience, triangular distributions are used in 90% of schedule risk analysis and to a lesser degree in cost risk analysis (as the this data is more readily available.)
Intaver Support Team
Intaver Institute Inc.
Home of Project Risk Management and Project Risk Analysis software RiskyProject
www.intaver.com

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