NHL Commissioner Gary Bettman said Tuesday that there was not enough data yet to draw conclusions about the link between concussions and a degenerative brain ailment that has been found in four dead hockey players. "They're still looking at a very limited database," Bettman said. "There's no control element because you have to look at everything that went on in a person's life before you can make a judgment as to what a brain may show when you open it up. ... There are no easy answers yet. I think it's unfortunate that people use tragedies to jump to conclusions that probably at this stage aren't supported."