What interests are in conflict? Can a chair's child study physics at that university? They probably get a tuition discount for doing so. The interests are actually all aligned, not in conflict, unless the university is an adversarial organization. The student wants to learn. The professor wants to teach. The chair wants to facilitate. If people behave ethically there is no issue.

There is a conflict between the faculty member's responsibility to grade fairly and their need to get good evaluations from their chair. There is a conflict between the chair's responsibility to write accurate evaluations and their desire for the child to get a good grade. Based on your own answer I thought you knew that.

Only if they behave unethically. But that is always true, so everyone has a conflict of interest with everyone if they are at odds because of unethical behavior. Think harder.

@Buffy There is a conflict of interest if conflicting actions are incentivized. Unethical behavior is not required for a conflict of interest to exist.

At the very least the situation presents the appearance of a conflict on interest, the disclosure of which is often required by conflict of interest policies.

Pushing a bit harder on the aligned interests. The child has an interest in doing well and impressing their parent. The parent has an interest in the child actually doing well, not just appearing to do well. If the parent steps in they negatively impact their reputation and that of the child. The chair's position is fraught, of course, but only if they behave badly. Suggesting that the instructor has a conflict is wrong. Their proper course of action is unchanged by the relationship. To suggest that they commit a transgression by teaching the child is, frankly, absurd.

@Buffy A conflict of interest is not a transgression. I already said that. Teaching the child is not a transgression. The instructor has a conflict of interest before they take any action. The likelihood of anyone doing anything bad in this situation is quite small. It's always a good choice to eliminate any appearance of conflict of interest, even if it's one that makes it easy to do the right thing.

@Buffy It only works if everyone involved is perfect already. I have a good friend who was in a similar situation in the early 2000's: While TAing a lower-level class, he came to believe (for good reason) that the son was cheating. At the same time, he was already struggling with the father's class. I don't think you can blithely dismiss the potential conflict.

This answer contains a kernel of truth, but I think it got heavily downvoted because it takes an overly broad (to the point of ridiculousness) view of what a conflict of interest is. This also leads you to misleadingly imply that OP is in a conflict of interest, where it is the chair who is in a conflict. What you are calling a conflict of interest (“if conflicting actions are incentivized”) is much more similar to the notion of a perverse incentive. Those are related notions, but are not identical. See my answer for further thoughts.

@Buffy Just in the province where I live the head of Italian-language schools (we are a multilingual autonomous province) is under investigation for allegedly pressuring a teacher to rise his son's grades. Article in Italian: ilfattoquotidiano.it/2022/05/17/…. The article says the investigation is now over and the prosecutor has found evidence of some misconduct. It's not clear yet if the case will reach the court.

The points are valid and technically correct. However, IMHO, it really misses other aspects, such as "what are the consequences of making this a special case"?. Because reality is that deans live close to the school they work at, and children will go to that school. It may be not "an idealistic situation", but it maybe also doesn't pose any real problems. And in reality - all other things considered as well - not making a special case out of the child, may be actually the best way forward.

-1: a) There is no COI here. If the chair of the department applies pressure, that's workplace/academic misconduct and a different question. Lacking such misconduct, the teacher has no practical relationship with the student. b) Also, the (nonexisting) COI you describe couldn't be resolved by any other means than outright banning the child from participating in any BSc/MSc/PhD program of the university involving any course given by teachers of that department, which, least to say, doesn't seem fair or reasonable.

@DanRomik A perverse incentive rewards making the situation worse. I see no relation between that and this question. No incentives have been offered at all. Trivial conflicts of interest are still conflicts of interest.

@Buffy FYI, I agree with your answer. It's just missing the detail that it's quite possible to remove the chair from the situation.

@Neinstein: "There is no COI here. If the chair of the department applies pressure, that's workplace/academic misconduct and a different question." That doesn't follow, because there doesn't have to be actual pressure/misconduct for a conflict of interest to arise: for example, the teacher may feel that they can't give the student low grades (/would be negatively affected if they did so) with no explicit pressure from the chair; what's more, even without that, an appearance that such pressure may be exerted can have negative effects (i.e. an appearance of corruption where none exists).

@Buffy, interesting, I usually consider "apparent conflict of interest" (i.e., when all parties behave ethically -- the chair not giving pressure to the teacher to give good grades to their child--, but "for avoidance of doubt" [people may still assume that there is some pressure], the teacher here avoids teaching the chair's child) as a conflict of interest as well. But I can see where you're coming from. Can we agree that in this answer, COI refers to both "apparent COI" and "actual COI"?

@psmears I think this is a bit of a stretch. COI has to stop at some reasonable level that doesn't hurt the object of conflict, i.e. the child. Pressures can be applied from and to anywhere. How would you avoid this conflict without outright banning him from the whole department? What about a child of an influental politican, should he be banned from all universities in the country to avoid COI? What about the child of the department head's wife's boss?... I don't believe that a percieved pressure that may or may not exist is a valid reason to assume COI. And if it does, it's a misconduct.

@Neinstein: Who's suggesting banning anyone? The problem is you're still confusing "misconduct" with "conflict of interest". It's not the same thing. A conflict of interest arising isn't (on its own) a sign of anyone doing anything wrong. Nor does it have to be eliminated - it should be managed proportionately. Sometimes this may just mean acknowledging it; sometimes putting arrangements in place to maintain oversight/transparency, and (very occasionally) replacing/removing/banning someone. Saying "Banning someone would be too much so this isn't COI" is putting the cart before the horse.

Why so many conflicts of interest? If I were child's parent I'd never want my child to be helped unfairly. That'd be such a bad teaching, I wonder how can you be chair of any educational organization if you don't respect teachers and don't value diligent work and meritocracy.

@Cris, by that reasoning we could just get rid of the ethical codes for all professions. (After all, no one could possibly become an engineer and ever become corrupt or develop a conflict of interest!) More to the point, however, for every serious, dedicated, ethical university administrator I've known, there has been an equally bad one. People accept positions for all sorts of reasons, including power.

@Cris You've misunderstood the answer. Having an interest in an action does not imply choosing that action.