Postdoc positions: turning down alternative offers safely and timely I have a situation that is probably quite standard, but I don't know the right way to act.

For several months I was looking for a postdoc job in computational neuroscience (probably exact field is not that important for the question but just in case) worldwide.

A couple of months ago a quite famous professor from a distant country (Japan) after a Skype interview told me that he is interested in me but he won't take the final decision until I give a job talk at his institution A. However he was busy for some time after our interview, so his institution bought me a airtickets (quite expensive ones) for a date after about two months. I have promised to inform him if I have other job offers.

Later I have actually received two other job offers from institutions B and C (both from USA), and I like one of them. So I said "yes" to the offer from B and they started to do the paperwork although they told me it should take a week or two for them to prepare an official appointment letter.

Here comes the problem: I was told by my colleagues that I should not turn down the job talk invitation from A and another offer from C, before I get the paperwork with B finished. However it is likely to be finished after I have to go the interview to that distant institution A. I have told the distant professor that I got an offer from B and that I put it on hold (at that time I did not finish making a decision yet). Later I realized that even if A professor makes an offer for me, I the offer from B is better, but I did not tell it to A yet. Professor from C also wants me to answer as soon as possible and wants me to discuss future projects.

So if I tell "no" to A and C now, there is a possibility that the paperwork process with B hangs for some reason (for example suddenly they may receive a better application from somebody else during these weeks) and I will be in an awkward situation. If I keep waiting for the paperwork in B to be finished, I would have to lie to A and C, and I would waste A's money on my ticket (though I would be happy to come to A and give the talk in any case, on my side), which is probably a not very scientifically moral thing to do.

Maybe I am wrong in being suspicious towards institution B, but I got an impression that postdoc position market in the US is very tough and everything might potentially happen and I do consider that it is a big luck for me to have an offer from B, as it is a quite famous place and I think there should be people with stronger CV's than mine, who might be interested in this position, announced publicly.

Could you please advise me, what would be the more academically correct way for me to act?
Here are some important points to consider:


Are you a bad person to take strategy x rather than y: no. You are fighting for your life here, while other institutions are fighting over having a nice person to talk to and some very minor travel allowance. Your needs take priority. Maximize your utility and don't think of anything else.
Will people or institutions remember any action or inaction on your part and hold a grudge forever? yes. people do that. it's a game theory thing that was set through natural selection. So, whatever you do is ok, but others may still get mad, to the point of even acting against their own interest just to hurt you. So even though you are morally allowed to do anything you want, acting in a way that will get people mad is not in your interest (and that's why we have the mechanism discussed above, to make other scared of making us mad).
Is the offer from institution B a sure thing: NO. Stuff does happen sometimes. You should not assume it will be ok.


So what can you do? First, you should let B know that you have other offers. You can also ask them if getting an offer from them is a sure thing or if instead you should pursue other possibilities for the time being. If nothing else, it will make them want you more.. If they say it's a sure thing and that you can stop looking elsewhere, and they respected people from a respectable institution, it's probably ok. But just to be sure, once you get such a response make sure to announce it to the world. Write on your homepage that you were promised an offer from them, put a copy of the letter on Facebook, do whatever you need to make sure that if they back out their image will suffer. Of course, in that case you should tell prof. A about your offer, explain that you would still be happy to visit and collaborate, and all the other yada yada. 

If you don't get a firm commitment from B, then you should act accordingly. You can let Prof. A know that you have information from B that they may make you an offer (make him want you more..), but don't let him know that you will definitely go there once an offer is finalized. If he has any decency he will not ask: travel money is small change and he is making a new connection, this is beneficial for all parties anyway. If he does ask, simply say that you have not made a final decision and you prefer to only decide once you have a firm offer in your hand. If you then get an offer from B before the trip to A you can let A know that you got the offer and it fits you for oh so many reasons that you doubt that you would eventually choose A. But you would of course be happy to collaborate in the future, or visit to give a talk, and yada yada.