The Flaw of Averages (2002)

This is extremely typical, I once had a head of production raise big concerns and initiate a lot of activities because: “Half the production orders take longer than the estimated time to produce!” Like this was some huge problem in our company. The real problem was that there was a lot of uncertainty, and in the line of communication “on average it takes 3 months to produce” got turned into “yes, dear customer we can guarantee that you’ll have the product in 3 months”.

Over time we got management to change this, but not enough that they wanted accurate data based estimates which we could of cause calculate from the well known distributions, but instead they just always added a buffer they pulled out of thin air. Why you ask? Because they felt that the original state of “half the orders taking longer than average” showed that “you can’t always trust the data”

Something grumble something… can’t believe we still have to explain this… grumble