What the research says

The Ferber method is known in research as graduated extinction. It has been studied for decades, alongside related approaches like full extinction (cry it out), bedtime fading and parent education. Here is what the main studies found, described as closely to their published summaries as we can. Each links to its PubMed record.

The short version

• Behavioral sleep approaches, including graduated extinction, reliably help young children fall asleep and stay asleep, according to a large review of 52 studies.
• Randomized trials have found improvements in babies’ sleep and, in some, in mothers’ mood and stress.
• A trial that followed families for five years found children’s emotions, behavior, stress and relationship with their parents were no different whether or not their families had sleep trained.
• One small study raised a question about infant stress hormones during full extinction. It has real limitations, and a later randomized trial did not find a stress problem.
• Results vary between babies, and studies describe groups, not your child.

The big review (2006)

A task force of the American Academy of Sleep Medicine reviewed 52 studies of behavioral treatments for bedtime problems and night wakings in infants and young children. They reported that 94% of the studies found the treatments effective, and that over 80% of children treated showed clinically significant improvement that lasted 3 to 6 months. The strongest support was for unmodified extinction and preventive parent education, with support also for graduated extinction, bedtime fading with positive routines, and scheduled awakenings.

Mindell et al., Sleep, 2006

Randomized trials

Infant sleep and maternal mood (Hiscock and Wake, 2002)

156 mothers of babies aged 6 to 12 months with severe sleep problems were randomly assigned to a behavioral intervention (controlled crying, taught over three consultations) or to written information about normal sleep. At two months, more sleep problems had resolved in the intervention group (53 of 76, compared with 36 of 76), and mothers’ depression scores tended to fall further. By four months, sleep problems in the two groups were similar, while mothers with high depression scores kept their improvement.

Hiscock and Wake, BMJ, 2002

Graduated extinction and bedtime fading (Gradisar et al., 2016)

43 babies aged 6 to 16 months were randomly assigned to graduated extinction, bedtime fading, or sleep education. Both active approaches produced large drops in how long babies took to fall asleep. Graduated extinction also produced large drops in night wakings and time awake after first falling asleep. Infant cortisol (a stress hormone) showed small to moderate declines in both groups compared with controls, and mothers’ stress fell. Twelve months later there were no differences in emotional or behavioral problems, or in attachment.

Gradisar et al., Pediatrics, 2016

Long-term effects (Price et al., 2012)

This long-term study followed children from an Australian trial. Babies had parent-reported sleep problems at 7 months, and their parents were either taught behavioral sleep techniques by nurses at 8 to 10 months or received usual care. At age 6, 225 families (69%) took part in follow-up. The researchers found no evidence of differences between the groups in children’s emotional or conduct problems, sleep, stress, closeness or conflict with parents, or in parents’ mental health. Their conclusion was that the techniques have no marked long-lasting effects, positive or negative, and that parents can use them to reduce the short- to medium-term burden of infant sleep problems.

Price et al., Pediatrics, 2012

The stress question (Middlemiss et al., 2012)

This study is often quoted as evidence that sleep training is stressful for babies, so it deserves a fair description. 25 babies aged 4 to 10 months took part in a five-day inpatient sleep program using full extinction (no check-ins). On the third day, babies no longer showed distress at bedtime, but their cortisol levels were still elevated, while their mothers’ cortisol had dropped.

It is a small study, in a hospital setting rather than at home, with no comparison group, and it studied full extinction rather than graduated extinction. It raises a question rather than answering it. The 2016 randomized trial above, which did include a comparison group, found infant cortisol declined slightly with graduated extinction rather than rising.

Middlemiss et al., Early Human Development, 2012

What the research does not tell you

• How your baby will respond. Studies report averages. Some babies change in a few nights, some take longer, and some do not respond well to a given method.
• Exactly which intervals are best. The chart in the app comes from Dr. Ferber’s book. Studies of graduated extinction have used a range of schedules.
• Anything about sleep problems with a medical cause. Reflux, ear infections, breathing problems during sleep and other conditions need a pediatrician, not a sleep-training plan.
• Very young babies. The trials above involved babies from about 6 months (4 months in one small study). Sleep training is not recommended before about 4 months, 6 months is a common starting point, and if your baby is under 6 months, talk to your pediatrician first.

Safe sleep comes first

No sleep-training method changes safe-sleep guidance. The American Academy of Pediatrics recommends placing babies on their back, on a firm, flat, non-inclined surface, room sharing without bed sharing, and keeping soft bedding and objects out of the sleep space.

AAP safe sleep policy, Pediatrics, 2022 · A parent’s guide to safe sleep (HealthyChildren.org)

All sources

1. Mindell JA et al. Behavioral treatment of bedtime problems and night wakings in infants and young children. Sleep. 2006;29(10):1263-76.
2. Hiscock H, Wake M. Randomised controlled trial of behavioural infant sleep intervention to improve infant sleep and maternal mood. BMJ. 2002;324(7345):1062-5.
3. Price AMH et al. Five-year follow-up of harms and benefits of behavioral infant sleep intervention: randomized trial. Pediatrics. 2012;130(4):643-51.
4. Gradisar M et al. Behavioral interventions for infant sleep problems: a randomized controlled trial. Pediatrics. 2016;137(6):e20151486.
5. Middlemiss W et al. Asynchrony of mother-infant hypothalamic-pituitary-adrenal axis activity following extinction of infant crying responses induced during the transition to sleep. Early Hum Dev. 2012;88(4):227-32.
6. Moon RY et al. Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment. Pediatrics. 2022;150(1):e2022057990.
7. Solve Your Child's Sleep Problems, New, Revised, and Expanded Edition (Richard Ferber, 2006)
8. American Academy of Pediatrics (HealthyChildren.org): A Parent’s Guide to Safe Sleep