The burden of proof is on those making the claims, not those who find the data dubious. The UFO advocates are asking us to believe something very important.
After all, there could hardly be any discovery more dramatic than visitors from other worlds. If they could prove that the aliens are here, I would be as awestruck as anyone. But I still await a compelling Exhibit A.
Seth Shostak is senior astronomer at the Seti (Search for Extraterrestrial Intelligence) institute, California).