You can absolutelly put it on to spreadsheet. Its just that its not a metric companies calculate normally.

I recommend everybody who is training new employees to track the time the training really takes, how much it takes away from your normal work effiency and how long it takes until newbies are ready to work shift solo. Do it enough times and you get average for new employers and you can calculate real life cost for new hires.

Then compare that to numbers the experienced guy would get during that time and how much money the employees training newbies would make. You get clear monetary difference between training new vs. keeping the old. If the experienced guy is competent they will always get better numbers on short term.

Then calculate median time people work in that position.

Now you can show a number that says: Hey, fire this guy and on average you loose this amount of money for new hire and if you want new employee who stays in the house as long as this guy you are firing has stayed, you need to go trough the training process this many times on average.

The cost of hiring and training a new employee is something a company of that size should know, and it's definitely more than the cost of a $2 cookie.

Exactly.