It sounds to me like your management is expecting some sort of 'gain' to be gotten from this exercise, which course is not unexpected, otherwise why waste everyone's time and company resourses. The issue is, WHAT exactly is it that they expect to gain? Or to put it another way, what 'problem' is it that they want to solve?
Now if the 'problem' is something like low-quality, poor productivity, too many workplace injuries, excessive machine and plant maintenance/repair costs, etc., then what you've been asked to do is very reasonable and everyone, when they're made aware of the issues, should generally accept the process and the intended goals and be willing to fully cooperate.
However, since you specifically mentioned that the workers wages would be directly impacted by what is learned, this sends up a red flag immediately. If the 'problem' that your management is seeing is that people are getting paid too much money and that this activity is intended to identify those individuals whose wages can be reduced,
then you're in big trouble. After all, if there are NO real expectatiosn that any of the previously mentioned production/safety related issues will be resolved with this effort but rather that there must be an overall reduction in the 'cost of labor', then that means that irrespective of how the workers actually get ranked after whatever tests or evaluations are completed, someone is going to look at that list and they are going to draw a line and everyone below it is going to get a cut in pay (or perhaps hours, but then that's the same thing) and I think I'm safe in saying that I doubt that anyone will look near the top of the list and draw a second line where those above it will get a raise. It does not sound like your management is looking for a 'net-zero' outcome here. They want to gain some sort of benefit and again, if it's NOT going to be with respect to that list of production/safety related issues then there is ONLY one thing left that it could possibly be.
So you have a choice, if it's truly related to those production/safety issues previously mentioned, then get going and do the best job that you can. But if there's any chance at all that it's nothing more than a 'snipe hunt' trying to find out who should get their pay cut, then no matter what you do next, first thing would be to update your resume since if you do go through with this and it does result in pay cuts or some other 'cost-reduction' outcome where the workers are the ones impacted, then I suspect that it would not be in your best intersts to continue to "work in the plant environment" or anywhere in that company for that matter.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
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