And, I am happy to report that we are in good company with many blogs listed that we follow here.
Of course, in a list as long as 50 there's always something to discover.
One for me was under the category of Operations Research Blogs: arandomforest.com, One blog on this site caught my eye: posted this past September, it is entitled "The Flaw of Averages and why everything is late" and refers to a book similarly titled: "The Flaw of Averages: Why We Underestimate Risk in the Face of Uncertainty" by Sam Savage.
Sam talks about the 7 Deadly Sins of Averages in his paper published in OR/MS Today from the Institute of Operations Research and the Management Sciences.
The Seven Deadly Sins of Averaging
1. The Family with 1 1/2 Children
2. Why Everything is Behind Schedule
3. The Egg Basket
4. The Risk of Ranking
5. Ignoring Restrictions
6. Ignoring Optionality
7. The Double Whammy
Of course for the risk astute project manager, "expected value" is the statistic of choice, not an arithmetic average. Expected value is a risk adjusted average of all the possibilities that go into an estimate. Thus, it is a richer piece of information, incorporating more of the information in the distribution of possibilities than just an average. Nevertheless, it does no harm to understand Savage's 7 points--just don't throw away useful information by not understanding expected value as well.
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