Here's the (abstract of the) paper I was thinking of https://pubsonline.informs.org/doi/abs/10.1287/opre.4.1.42
Appalling that I can't find a free version of a 70 year old paper. You might be able to find the full text somewhere... I would of course never encourage anything that might run afoul of the scientific publishing protection racket.
Hard to tell from the picture but it may be a mud dauber, which is not a very aggressive wasp (to humans) and is useful for controlling spider populations. if they're getting up into your ceiling near the light fixture, blocking it off may prevent it from trying to nest there. if it's building on the fixture itself, knocking down the nest might convince it to relocate to a safer area. I've never had a mud dauber sting me even while knocking down nests, but I would still wait until it's off gathering mud to make an attempt on the nest.
https://en.wikipedia.org/wiki/Mud_dauber