Do nonphysical punishments reduce antisocial behavior more than spanking?

A comparison using the strongest previous causal evidence against spanking
Robert E Larzelere, Ronald B Cox Jr, Gail L Smith
Published in BioMed Central Pediatrics April 2010

This study concludes that all corrective actions by parents and psychologists appear to increase children’s antisocial behavior due to child effects on parents. Improved research methods are needed to discriminate between effective vs. counterproductive implementations of disciplinary. How and when disciplinary tactics are used may be more important than which type of tactic is used.
http://www.biomedcentral.com/content/pdf/1471-2431-10-10.pdf