The study author says:
The claims that are made for not spanking children fail to hold up. I think of spanking as a dangerous tool, but then there are times when there is a job big enough for a dangerous tool. You don’t use it for all your jobs.In other words, sometimes a mom's just gotta whack the kid.
I dunno. I'll grant that people vary, and it may be that speaking to some kids lightly by hand, in a non-violent, non-ranting, non-physically-damaging way might get their attention better than saying mommy doesn't like it when you try to set fire to the cat. But I sure wouldn't trust it as a standard operating policy for parents. For one thing, the parents who would like it best I suspect are the ones who would overdo it. For another, since people vary, and some kids are helped and some hurt by it, how do you know what kind of kid you have?
No, I'm still glad I never hit a kid. If they want to be better students, they'll have to do it by self-flagellating.