Comments on: Fundamentals of Range Estimating in Project Management http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management Tue, 22 May 2012 19:56:26 +0000 http://wordpress.org/?v=abc hourly 1 By: Glen B Alleman http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management/comment-page-1#comment-18958 Glen B Alleman Wed, 17 Mar 2010 15:46:24 +0000 http://www.pmhut.com/?p=4994#comment-18958 Bill, It is absolutely clear. It is also clear that range estimates have VERY serious systemic problems on real projects. Ignoring this usually results in very unpleasant surprises in practice. Bill,

It is absolutely clear.

It is also clear that range estimates have VERY serious systemic problems on real projects.

Ignoring this usually results in very unpleasant surprises in practice.

]]> By: Bill Duncan http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management/comment-page-1#comment-18951 Bill Duncan Wed, 17 Mar 2010 11:43:41 +0000 http://www.pmhut.com/?p=4994#comment-18951 Glen -- I thought it was clear in the article that by "range estimates" covered distributions. Triangular distributions are illustrated and discussed in the article. Glen — I thought it was clear in the article that by “range estimates” covered distributions. Triangular distributions are illustrated and discussed in the article.

]]> By: Glen B Alleman http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management/comment-page-1#comment-18922 Glen B Alleman Wed, 17 Mar 2010 04:19:47 +0000 http://www.pmhut.com/?p=4994#comment-18922 Dina, All credible PM applications provide abilities to have ranges. Not sure what software would not. Dina,

All credible PM applications provide abilities to have ranges. Not sure what software would not.

]]> By: Dina Garfinkel, PMP http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management/comment-page-1#comment-18917 Dina Garfinkel, PMP Wed, 17 Mar 2010 02:28:06 +0000 http://www.pmhut.com/?p=4994#comment-18917 Great lesson here on ranged estimates. But to correct you on this one point: "I tried range estimates once before, but my project management software only has room for one estimate!" There IS a PM software that allows for ranged estimates. LiquidPlanner (http://www.liquidplanner.com/) was built around the whole concept of ranged estimates, giving the PM the ability to make a truly reliable project schedule. In fact, the CEO of LiquidPlanner, Charles Seybold, just made an excellent blog post about the power of data with analyzing a ranged estimate here: http://bit.ly/9YcbxS Great lesson here on ranged estimates. But to correct you on this one point:

“I tried range estimates once before, but my project management software only has room for one estimate!”

There IS a PM software that allows for ranged estimates. LiquidPlanner (http://www.liquidplanner.com/) was built around the whole concept of ranged estimates, giving the PM the ability to make a truly reliable project schedule. In fact, the CEO of LiquidPlanner, Charles Seybold, just made an excellent blog post about the power of data with analyzing a ranged estimate here: http://bit.ly/9YcbxS

]]> By: Glen B Alleman http://www.pmhut.com/fundamentals-of-range-estimating-in-project-management/comment-page-1#comment-18912 Glen B Alleman Wed, 17 Mar 2010 00:12:56 +0000 http://www.pmhut.com/?p=4994#comment-18912 Bill, While range estimates are a starting point, they have been discouraged and sometimes disallowed in several project domains. In their place are probability distributions (Triangle is good in the absence of any underlying historical data), and the variance spreads around the Most Likely value for cost or duration. See DID 81650 as a guide. The primary reason for this the well documented estimating bias of asking for upper and lower limits. The research started in the Naval Research Laboratory and is now used in oil&gas well reserves, DoD, DOE, and DHS cost and schedule estimates. There is a significant variance between the numbers dependency on what order they are asked. There are three permutations of how the numbers are captured. laboratory studies and field confirmation shows up to 27% variance in the elicited values, depending on the sequence. Glen B. Alleman VP, Program Planning and Controls Aerospace and Defense Business Sector References available on request... Bill,

While range estimates are a starting point, they have been discouraged and sometimes disallowed in several project domains.

In their place are probability distributions (Triangle is good in the absence of any underlying historical data), and the variance spreads around the Most Likely value for cost or duration.

See DID 81650 as a guide.

The primary reason for this the well documented estimating bias of asking for upper and lower limits. The research started in the Naval Research Laboratory and is now used in oil&gas well reserves, DoD, DOE, and DHS cost and schedule estimates.

There is a significant variance between the numbers dependency on what order they are asked. There are three permutations of how the numbers are captured. laboratory studies and field confirmation shows up to 27% variance in the elicited values, depending on the sequence.

Glen B. Alleman
VP, Program Planning and Controls
Aerospace and Defense Business Sector

References available on request…

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