The Romans invented decimation as a practice to punish mutinous legions. Instead of killing all soldiers - which would have been a terrible waste of good labour - they forced the legionnaires to kill one in every ten of them as a punishment for the whole group. This served as a public reminder of their guilt and forced them back into obedience, while preserving troop strength at 90%. Never not pragmatic those Romans…

20th Century Managers (20M) will use decimation to publicly shame offenders – for good reason or not – and to send a message to the rest of the team. It is seen as an efficient way to communicate what is inacceptable to the boss and what he considers to be a mistake. Why tell only one person, if you can educate 9 others at the same time? It can be accompanied by yelling, drumming on tables and other impressive theatrics to make the point stick.

What the 20M misses, is that nowadays the effects will be very different:

Firstly, the supposed offender will be embarrassed in front of his colleagues. He will feel treated without any respect. The trust relationship is in the bin. Good luck motivating him to change his ways or to not to fail again! The opposite will probably occur: hurt, scared and trying to please his irate boss, more mistakes will be made.

Secondly, the rest of the team will see only weakness in a Manager who cannot keep his temper and uses public shaming as a weapon. This news item will spread like wildfire in the organization and destroy the Manager's standing. Decimation still works, only not the way it was originally intended by the Romans.

The 21st Century Manager (21M) will use the tool of personal feedback: In a one-on-one setting he will describe his observations and interpretations with his employee and coach him on how to change and grow. This has the chance of having a positive impact on the relationship and help the employee grow. A good 21M will prepare such a session with a clear structure and message, to manage emotions. Practice is important! If it is a very critical message, use someone safe to run it by and tweak it.

Do not forget to ask for feedback in return: it will increase trust and you may actually learn something about yourself…

TL; DR: Never embarrass your people in public but help them grow from their mistakes!