I'll be travelling to London for a business matter I can't discuss (let's say our dear colleagues there are not doing exactly what we expected them to)
Basically, we had an employee change her job and a former colleague of mine (we shared the same office for a couple of months in 2002/2003)will take over her work.
We'e finally been able to pinpoint the problem with her : she had changed the whole process she was supposed to detail for us, but forgot to apply some rules (ex : orders of magnitude were sometimes 3000% off).
D'you know why ? Because she'd forgotten english and french units were not the same (1 giga therms =/= 1 MWh)....
Three months in a row she gave us false data sets that forced us either to ignore some effects or to checks things for quite some time in order to filter information.
On month was enough, two was way over our limits. Three was worth firing her.
I'd never been the one personne asking for an employee's "head". It feels... bad.