Is this true?
Also, are there any obligations about the minimum amount of research papers you should produce (say every year) after being tenured? What if a tenured professor does not produce a paper for say a year or two?
Academia Stack Exchange is a question and answer site for academics and those enrolled in higher education. It only takes a minute to sign up.Sign up to join this community
Normally this is something that is negotiated between faculty and administration on an annual basis (or so) and is more related to future salary and duties than to tenure. Usually ending tenure requires provable misbehavior.
Expectations differ by institution and department, of course. But there are certainly situations in which a tenured professor is working hard, but on a difficult problem, and doesn't produce anything publishable for some time. If they are otherwise productive (doctoral students are being produced, say) then things are probably fine.
People also tend to wind down as the approach retirement and this is also allowed most places, though the person won't get much in the way of salary increases and will probably see an increase in teaching/advising load.
Also, what is considered "productive" in one field may be considered unproductive in another. I'm always reminded that Einstein worked for ten years on Special Relativity prior to the 1905 paper. It was a hard problem worked on unsuccessfully by many people including the luminaries of the day.
Quality of research is valued, not just quantity. And if the quality is poor, the quantity doesn't matter much.
But a faculty member needs to convince the chair and dean that what they are doing is appropriate, though tenure is very unlikely to be at risk.
Note also that the freedom to set the direction of your research is the more important question. That freedom lets you delve into odd and obscure corners without fear of losing your job.
As for the freedom of research: The situation with research is not so different from the freedom of speech in many countries. Yes, you can say whatever you want. But (i) you don't have the right that anyone actually has to listen, (ii) you don't have the right that anyone actually likes it. You just can't be punished for it.
This is how it is with research: The university might not be able to fire you because your interest lies in researching the obscure animal stone louse, and spend all of your research time on it. But you might not get published, and you might not get funding for it either. And that is something the university might care about, and reasonably so I might add. That's because ultimately universities have an obligation to society, and if what you do has no outcomes, then you're not doing your job. The university can then reasonably withhold promotions, pay raises, and other perks such as workload assignments that allow you to prioritize research over teaching.
As a consequence, choosing a research area that is publishable and fundable puts some constraints on what you do.