As you might suspect, this method can be very difficult, depending on temperament, and can take many days or weeks. It can be difficult to avoid engaging with your child (and “watching them cry” is very difficult), and it will likely be a little confusing to the child (particularly younger ones) when you don’t. However, with time and consistency, this can be a good option for parents who do not want to leave their child alone to cry but who haven’t had success with other methods, either.
This method involves more tears than the previous two; however, you don’t leave your baby unattended in the room at all. Here’s how the chair method works: start by doing your normal bedtime routine. Then, put a chair very near the crib, bassinet, or bed and sit on the chair as your baby falls asleep. The goal is not to help your child fall asleep, nor to help her calm down necessarily, depending on how you implement it. You are generally not supposed to give your child any attention. The reason you are in the chair is only to reassure them that you are there with them and have not left them alone. Each night you move the chair farther and farther away from the crib until you are right outside the door until eventually, you no longer need the chair at all.
"By the time your baby is 3 months old and has developed a fairly predictable 24-hour pattern, it becomes more important for you to provide increasingly consistent structure. If you do your best to establish a reasonable and consistent daily routine and keep to it as much as possible, then it is likely that your child will continue to develop good patterns. If instead you allow the times of your child's feedings, playtimes, baths, and other activities to change constantly, chances are his sleep will become irregular as well."
C.I.O. is the most famous sleep training technique, and the most controversial — although, despite its daunting name, it is safe and effective. In its simplest form, unmodified extinction, you place your infant down at bedtime, drowsy but awake, and then leave the room, without returning to check on or soothe your baby. This method will work quickly, but often produces prolonged periods of crying for a few nights, which can be difficult for parents to tolerate.
Sleep training is a loaded phrase, and one that is often used synonymously with letting your baby self-soothe, or “cry it out,” but that’s not the whole picture, says Alanna McGinn, a certified sleep consultant and the founder of Good Night Sleep Site. “It’s more about being able to teach your baby that they are capable of falling asleep independently,” she says. You want your baby to be able to nod off on their own—ideally without nursing, rocking or using a pacifier—because whatever tools they use to fall asleep at bedtime are the same things they’re going to wake up looking for during the night. Yes, this can feel unloving and even downright cruel. You’ll find experts on both sides of the issue: Breastfeeding advocates say it’s normal for babies of all ages to wake up multiple times to nurse, and even the sleep coaches interviewed for this article disagree with how much crying and distress are acceptable.