As the researchers and authors report, modern parents have “unproven concerns” about the “patting on the bottom” technique (which they would call “controlled comforting”) and other behavioral interventions. But after a five-year follow-up of families’ participating in a randomized trial, no long-term differences, either positive or negative, were found between families helped to use behavioral techniques to teach infant sleep and those left to their own devices.
But the targeted intervention did help at the time: families who were given techniques to teach their babies to sleep did report lessened infant sleep problems and maternal depression. “We therefore conclude that parents can feel confident using, and health professionals can feel confident offering, behavioral techniques such as controlled comforting and camping out for managing infant sleep.”
Sleep Training Won't Hurt, May Help- http://parenting.blogs.nytimes.com/2012/09/11/sleep-training-wont-hurt-might-help/ 
Interesting article! How does it make you feel about your decision to use sleep training with your child?