Better reported wellbeing is not that important.

I would also report being happy if I think saying the opposite could cost me this nice additional income.

That's a rather pessimistic and evil stance to assume other people to have. At the same time: if that was someones incentive, wouldn't that also cause happiness or well-being to increase anyway?

My point is that reported data is generally very unreliable, since there’s all kind of incentives that bias the results.

As for that generating happiness, think of drugs for instance, that you personally want them doesn’t mean they’re good to you.

What makes it evil? That word is thrown around too easily. If there is an incentive, it has to be considered as a possible explanation

It is evil to assume everyone else is evil and the only difference between people is those who have been caught doing evil things and those who are hiding it well. It assumes there are no well-intentioned people or people who wouldn't feel the need to lie.

Why would you assume that I’m assuming everyone is evil?

I’m just assuming that people generally follow incentives and thus averages will reflect them. If you need any evidence for “People follow incentives”, we have full branches of studies built on that premise.

My guess would be that you’re assuming I think people would lie, and you find lying reprehensible (I don’t).

In any case, IMO the biggest problems here are that apples to apples comparisons are very hard to make, and long term effects are essentially unknowable.

So the additional income is "nice", but wouldn't that mean it is improving your wellbeing? Removing the extra income would reduce your happiness, would it not?

Not necessarily. That the additional income is “nice” means that you personally think it has improved your wellbeing, not that it has.

I might think that bacon makes me feel happier, until I need a bypass 10 years later.

Fair enough. Re-reading your comment now and I understand your point better.