Change profession

In the page where i can change professions, there is a clumn with "Needed for 100% Production", it means in addition to the ones i already have??
And then i should have unemployed zero

i don't understand this

The "needed for 100%" category are unemployed but potentially employed given current circumstances. For example:

You have 2M employed low level workers. You have 1M unemployed low level workers. You now order 2 new factories who require 100k low lever workers each (200K total). The factories are ordered, but not build yet. 2 x 100k = 200k = needed for 100%.

So you will see in this example after ordering the stats will show: 2M employed, 1M unemployed, 200k needed for 100% production. This means 800k are available where first 1M was. They are included in the 1M unemployed but will soon be employed when the 2 factories are built.

Ok i think i understand, even if It happens when i dont have any factory building...

If it is a low number, I guess it comes from workers retiring that month. Not sure. If they are nurses, teachers, docters, it's from hospitals and schools building.

Point is, you should take into account that the number that are reserved for 100% are actually your "hired next game-month or some game-months later" unemployed portion of the unemployed. If you build an additional factory or change a profession whereby your unemployed total becomes lower than the "needed for 100% production" for that profession, it creates a shortage. However, the next game-months there will also be new graduates (and new retirements).

You can have unemployed workers and still have it show needed for 100% employment if there are shortages elsewhere. For example, say you have 0 available high tech engineers, but have everything else available. The factory won't run without the high tech engineers, so all of the other workers will be laid off until you get enough engineers. Those laid off workers would show up in the "needed for 100%" column, even if you have them available to work.

Of course, now i understand