Hogg agrees with Sears that sleep associations should be positive but disagrees with his techniques. She cautions against letting your baby depend on "props" such as nursing, patting, and rocking to get to sleep. Instead, Hogg's approach calls for going to your baby when he cries, picking him up, and putting him back down as many times as necessary.
The most well known cry it out technique is the one developed by pediatrician Richard Ferber, director of the Center for Pediatric Sleep Disorders at Children's Hospital Boston. Ferber says that in order to fall asleep on their own and sleep through the night, babies have to learn to soothe themselves. Ferber believes that teaching a baby to soothe himself may involve leaving him alone to cry for prescribed periods of time.
In the first several weeks of life, babies are hungry at night, leading to an apparent reversal of day and night and erratic sleep patterns. Fortunately, this usually resolves by about 3 weeks of age, after which your child settles into a three- or four-hour cycle, typically following a pattern of waking, feeding and sleeping. At this point, exposing your baby to natural light during the day can help encourage longer periods of daytime wakefulness and more sleep at night.
"My well-meaning friends are all Ferber addicts. I went against my own instincts with our son and tried with no success. They promised it would get better each night, but on the third night he cried for three hours, much longer than the first two. I felt like a failure and, of course, stressed from all of his crying. Babies have their own personalities, and you shouldn't feel pressured into doing something that 'works for everyone else.'"

Most experts recommend starting when your baby is between 4 and 6 months old. By about 4 months, babies have typically started to develop a regular sleep-wake cycle and dropped most of their night feedings. These are signs they may be ready to start sleep training. Many babies this age are also developmentally able to sleep for long stretches at night.
No one likes to talk about sudden infant death syndrome (SIDS); it is a terrifying topic. SIDS is defined as the sudden death of an infant, which remains unexplained after a thorough investigation. These deaths occur in the first year of life, with the highest risk occurring between 2 and 6 months of age. Fortunately, these deaths are becoming less common, thanks in large part to the early ’90s Back to Sleep campaign, which urged parents to place infants to sleep on their backs. Suffocation is also a major risk for infants if they do not sleep in a safe sleeping environment.
While you may have read up on various sleep training methods while pregnant or in the early weeks of baby’s life, it’s a good idea to speak with your pediatrician before you start. For example, if your child is gaining weight slowly or was a preemie, he may not be ready to drop a nighttime feeding and may need a sleep-training schedule that’s adapted to a few middle-of-the-night wake-ups.
McKenna advises against sleep training and encouraging babies to sleep for long stretches at night. Instead, he urges parents to follow their babies' cues and allow them to wake frequently through the night to feed. A strong advocate for co-sleeping, McKenna encourages bed-sharing and other co-sleeping arrangements, such as putting the baby in a bassinet or crib at the parent's bedside, while also following standard SIDS safety precautions – for example, making sure there are no blankets or stuffed animals around him.

"There are good times to sleep-train and periods when it may be less likely to work," says developmental psychologist Isabela Granic, Ph.D., coauthor of Bed Timing: The 'When-To' Guide to Helping Your Child to Sleep. "This is because infants and toddlers go through mental growth spurts that make them especially clingy, fussy, and prone to night wakings. They're learning new cognitive skills and often don't sleep as well."
This is considered a ‘cry’ method of sleep training. This technique entails allowing your baby to cry while checking on him at intervals. The goal here is to reassure him every so often that you are nearby and to reassure yourself that he is okay. When you go to check on your baby, you are not “supposed” to pick him up nor engage him much, but simply reassure him using your voice and a loving pat for 2-3 minutes, tops (watch the clock!). With this sleep training method, the goal is NOT to help baby fall asleep – that is what he is learning to do on his own! Instead, the idea is that he falls asleep on his own, in the same “environment” in which he will awaken periodically throughout the night. The knowledge of how to fall asleep unassisted at bedtime will pave the way for him/her to go BACK to sleep throughout the night. Over time, you gradually increase the amount of time between your ‘checks’. See a more detailed step-by-step explanation of this method here: The Ferber Method
After going through your bedtime routine, put your baby in their crib, leave the room and wait a specific amount of time (say, a minute). Then go in and reassure your baby with words like “Mommy loves you” or some kind of touch, such as a rub or pat. McGinn says it’s preferable not to pick the baby up. Garden, on the other hand, reserves this method for babies seven months and older. (In her opinion, younger babies require a parental presence so they know they haven’t been abandoned, especially if they’ve worked themselves up into a frenzy.)
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