It is indubitably better for the postdoctoral training stint if the prospective candidate visits the laboratory before either side commits. The prospective gets a chance to see the physical resources, gets a chance for very specific and focused time with the PI and above all else, gets a chance to chat with the lab's members.
The PI gets a better opportunity to suss out strengths and weaknesses of the candidate, as do the existing lab members. Sometimes the latter can sniff things out that the prospective candidate does not express in the presence of the PI.
These are all good things and if you prospective trainees are able to visit a prospective training lab it is wise to take advantage.
If memory serves the triggering twittscussion for this post started with the issue of delayed reimbursement of travel and the difficulty some trainees have in floating expenses of such travel until the University manages to cut a reimbursement check. This is absolutely an important issue, but it is not my topic for today.
The discussion quickly went in another direction, i.e. if it is meaningful to the trainee if the PI "won't pay for the prospective to visit". The implication being that if a PI "won't" fly you out for a visit to the laboratory, this is a bad sign for the future training experience and of course all prospectives should strike that PI off their list.
This perspective was expressed by both established faculty and apparent trainees so it has currency in many stages of the training process from trainee to trainer.
It is underinformed.
I put "won't" in quotes above for a reason.
In many situations the PI simply cannot pay for travel visits for recruiting postdocs.
They may appear to be heavily larded with NIH research grants and still do not have the ability to pay for visits. This is, in the experience of me and others chiming in on the Twitts, because our institutional grants management folks tell us it is against the NIH rules. There emerged some debate about whether this is true or whether said bean counters are making an excuse for their own internal rulemaking. But for the main issue today, this is beside the point.
Some PIs cannot pay for recruitment travel from their NIH R01(s).
Not "won't". Cannot. Now as to whether this is meaningful for the training environment, the prospective candidate will have to decide for herself. But this is some fourth level stuff, IMO. PIs who have grants management which works at every turn to free them from rules are probably happier than those that have local institutional policies that frustrate them. And as I said at the top, it is better, all else equal, when postdocs can be consistently recruited with laboratory visits. But is the nature of the institutional interpretation of NIH spending rules a large factor against the offerings of the scientific training in that lab? I would think it is a very minor part of the puzzle.
There is another category of "cannot" which applies semi-independently of the NIH rule interpretation- the PI may simply not have the cash. Due to lack of a grant or lack of a non-Federal pot of funds, the PI may be unable to spend in the recruiting category even if other PIs at the institution can do so. Are these meaningful to the prospective? Well the lack of a grant should be. I think most prospectives that seek advice about finding a lab will be told to check into the research funding. It is kind of critical that there be enough for whatever the trainee wants to accomplish. The issue of slush funds is a bit more subtle but sure, it matters. A PI with grants and copious slush fundes may offer a better resourced training environment. Trouble is, that this comes with other correlated factors of importance. Bigger lab, more important jet-setting PI...these are going to be more likely to have extra resources. So it comes back to the usual trade-offs and considerations. In the face of that it is unclear that the ability to pay for recruiting is a deciding factor. It is already correlated with other considerations the prospective is wrestling with.
Finally we get to actual "will not". There are going to be situations where the PI has the ability to pay for the visit but chooses not to. Perhaps she has a policy never to do so. Perhaps he only pays for the top candidates because they are so desired. Perhaps she does this for candidates when there are no postdocs in the lab but not when there are three already on board. Or perhaps he doesn't do it anymore because the last three visitors failed to join the lab*.
Are those bad reasons? Are they reasons that tell the prospective postdoc anything about the quality of the future training interaction?
*Extra credit: Is it meaningful if the prospective postdoc realizes that she is fourth in line, only having been invited to join the lab after three other people passed on the opportunity?