Since Bryan Caplan believes that parents don’t make their children into who they’re going to be for the rest of their lives, people sometimes interpret Bryan as saying not to discipline. But this is a misunderstanding. Twin and adoption studies only show that parent’s long term effect on their children is negligible. So discipline effects children with the short term in mind. Make them good housemates. Sure kids aren’t like clay, but they are like a flexible plastic – they respond to pressure, but don’t expect them to stay that way forever.
Caplan has a good post on discipline at Econlog. It is also in his book, Selfish Reasons to have more Kids. In a nutshell, discipline is about clarity, consistency, and consequences. Adopt firm rules, clearly explain the penalties for breaking the rules, and impose promised penalties to the letter.
If you're skeptical of the wisdom of the ages, there is solid experimental evidence in its favor. When parents ask psychologists to help control their children's disobedience, tantrums, and aggression, psychologists often respond by training the parents.They call it "behavioral parent training," but it's Clarity, Consistency, and Consequences by another name.[i] Researchers have run dozens of experiments to see whether behavioral parent training actually works. It does. Suppose you have a list of parents who want help with their problem children. You randomly train some, and leave the rest on a waiting list. Experiments typically find that the average child of the trained parents behaves better than 80% of the children of the parents on the wait list. [ii] The main weakness of behavioral parent therapy is parental backsliding: Once parents tire of Clarity, Consistency, and Consequences, their kids go back to their old tricks.[iii] Discipline is like dieting: It works when tried.
What about when other people undermine your parenting method? Children learn that their relationship with different people will be on different terms. In the words of Princess Arendelle, “Let it go.”
When you're trying to improve your kid's behavior, other authorities - teachers, grandparents, nannies, and so on - often frustrate you by undermining your rules. What good is it to practice the Three C's if no one else does? Selfishly speaking: Plenty of good. Kids quickly discover that different people have different rules. If the typical teenager treated his friends the way he treats his parents, he wouldn't have any friends. A central criticism of behavioral parent therapy is that it "only" improves children's behavior in the home.[iv] But an optimist would draw a different lesson: Parental discipline is enough to make children treat their parents decently. If other authorities in your child's life have lower standards, that's largely their problem.
Here is a parenting website that disagrees with Caplan. I disagree with them.
Here is Bryan Caplan on Econtalk discussing Selfish Reasons to have more Kids
