I don't know. For some jobs seniority is a huge pay factor. Other employers that want to fill low skill positions may want a steady supply of young cheap labor. For these employers seniority may be a negative. [I've know a lot of people that were let loose from a job because they'd been there too long and made too much money] I'd say seniority is a variable factor that can't be quantified - at least for employment discrimination laws.
That last bit sort of makes a point I was trying to raise. If employers are letting people go because they are making too much and they want to bring in less experienced people they can pay less, that suggests that at least for those positions, longevity pay isn't warranted. Won't be true for all jobs, of course, but I suspect it's true for a lot more jobs than we think it is.
It's sort of a catch-22. We convince people that time in service is a reasonable basis for continuing raises, so they expect those raises. But if the 6-week guy and the 15-year guy are each producing 30 widgets a day, how can you justify much pay disparity?
For most jobs, there's a learning curve and it makes sense that someone at the beginning of that curve would get paid less. A century or 2 ago, apprenticeships were served in occupations that had a steep learning curve.
Today, a lot of jobs have a probationary period where the pay is less and it's easier to get rid of an employee. But at some point - and I suspect it's often earlier than we might think - the job is learned. Get a raise. At some further point, reliability has been demonstrated. Get another raise. Beyond that - for most workers in most jobs - what's the reason for additional raises? The occasional star gets promoted out of the comparison pool. Do those who settle in and do the same good job, year after year, deserve raise after raise?
To bring it back to the women thing, if it takes a year to master a job and we are talking about a man and a woman who do the job equally well but the woman at some point took off a few years to raise kids, does that really justify a wage disparity? I don't think so, in most cases. Which is why I referred to such disparities as entitlements. We have been conditioned to believe we deserve continuing raises for longevity, but do we really?
