Don't threaten to resign. Make your argument, back it up with data and evidence, let managers the space to do the job they are supposed to do. If then they don'

Don't threaten to resign. Make your argument, back it up with data and evidence, let managers the space to do the job they are supposed to do. If then they don't fix the problem, then just leave. There is only downside for threatening to leave, it scuppers your future in the company. As michaelt notes, don't bluff, have the next step lined up. At that point, there's no value in threatening to leave. Just hand in your notice, if they realise your value they tend to counter-offer anyway. But be sure leaving is the right thing for you.