There should have been a maybe for this answer. There is no clear answer for this questions because each child is different. Two out of my three children it worked for then along came the third one and spanking didn't work. Honestly it made him more aggressive and he seemed confused and it didn't seem to deter him one bit.
I have worked with many children throughout my years and most children if you pop their hand they learn not to touch what you are telling them not to. If a child touches a stove and burns their hand they don't touch the stove again. Now, I'm not saying they should be burnt. What I'm saying as through life each one of us learns from "uncomfortable" consequences. We make choices that dictate to us where and how our life will turn out.
I feel that nowadays we are so focused on the immediate consequence we don't look down the road at the future. We are accustomed to being comfortable and as parents we don't want to see our children suffer any consequences we unintentionally create monsters. As a mom, I hate telling my kids no. I hate seeing that sad face but it's important that they have limits. A pop on the rear end or on the hand will quickly teach them that what they are doing is wrong.
I know with abuse on the rampage it seems we would all be heading the other way but in all honesty children who are abused by their parents aren't being abused because they are getting a spanking for discipline. There are other underlined problems involved that usually have nothing at all to do with spanking the child. As time goes on things are going to continue to get worse. Until parents are willing to step up and take control of appropriate discipline in their families things are going to continue to go wrong and children are going to increasingly get worse.
Looking back at history we see that when there was spanking allowed in the classrooms there were limited behavior problems. People look at the state our schools are in and say "we don't know what happened". Well for one thing there is no discipline in the schools and we are seeing the fallout from it. Our jails are fuller then they have ever been, the juvenile court is packed, drugs and alcohol abuse are on the increase and where did it all start falling apart? Its not about hurting children its about providing consequences for problem behaviors. Spanking is not the only form of disapline your child needs but its really important to address it while they are young.