Earlier research that began in the 1980s found that workers ages 55 and over found employment in relatively few occupations, with employers responsible for the decisions that made this the case.

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The report said that another study confirmed obstacles to jobseekers who were 50 and over that were created by personnel policies in the 1990s, as well as finding that jobs requiring substantial training, computer use, numerical aptitude and union membership were more closed to older jobseekers.

In addition, the study found hiring of those older workers was concentrated in “‘old person’ occupations: low-paying, low-status jobs, such as night watchman, retail clerk, or crossing guard.”

But four factors changed that situation somewhat, improving the chances for older workers to find work in a broader field of opportunities.

One factor was the shift away from defined benefit pensions, which meant employers were no longer concerned about backloaded benefit accruals. Another is a move away from traditional personnel policies in a more knowledge-based economy.

A third is the higher education level of older workers compared with younger ones, which cuts down on the age disadvantage, making them more attractive to employers.

And fourth, as boomers age, hiring managers themselves are older and are evaluating their peers — and valuing older workers more than younger hiring managers do.

Wages for those “old person” jobs, in addition, appear lower than jobs that hire both younger and older workers.

However, the study said that the differential did not account for how those jobs differ from ones that hire across all ages. “Old person” jobs, it said, differed from other jobs by requiring less in the way of physical skills or numerical ability, and when that was taken into account, such jobs “paid no less” than others.

The report did warn, however, that its results “should be interpreted with a degree of caution,” since of necessity it could only account for people who had actually been hired — not jobseekers who failed to find work.

But it concluded that, while employment opportunities do decline for workers changing jobs after age 50, there has been a broadening of occupational opportunities since the late 1990s, particularly for better-educated women.