Hah, this was a running a joke at my last place of work ('Double it, change the units') where we were developing for clients and so were often publishing estima

Hah, this was a running a joke at my last place of work ('Double it, change the units') where we were developing for clients and so were often publishing estimates externally. More recently they moved into the world of science and actually fed back the results of previous estimates into the estimation process, to try and address systematic mis-estimation. Yes, each estimate may not be right, but it's surprising how if you average them out you can get them pretty close.