The ECAS study attributed 36 per cent of total SIDS deaths to sleeping alone in a room.Another key debate in sleep training revolves around getting the right balance between parental soothing and expecting baby to be independent. Attachment parenting is a parenting philosophy characterized by practices such as baby-wearing (carrying infants in slings or holding them frequently), long-term breastfeeding, co-sleeping (sharing the parental bed with the baby), and promptly responding to a baby's cries. Popular sleep training methods, such as the Ferber Method, rely on letting the baby cry for a certain number of minutes, to allow the child a chance to fall asleep more independently and move away from an over-reliance on parental assistance to fall asleep. Advocates of attachment parenting generally reject traditional sleep training methods that involve allowing a baby to cry, asserting that such practices do not align with meeting the child's immediate needs.A study conducted also showed that sleep trained babies displayed elevated cortisol levels (a proxy for stress, although this study did not have control babies without sleep training), but were simply not signalling to their parents.Another method is Behavioral Infant Sleep Intervention to effectively reduce infant sleep problems and associated maternal depression in the short- to medium-terms. This method randomized tried and found effective at reducing the short- to medium-term burden of infant sleep problems and maternal depression One study shows that 80% of infants from Asian countries shared a room with their parents. These parents reported less overall sleep compared to the Caucasian countries where 50% of infants were reported to be sharing a room with their parents during the infants' first couple months of life.One study reported parents waking up in the night less and feeling more parental competence in the group that was taught these behavioral techniques.Sleep coaching industry has been criticized for being unregulated, suffering from excessive fees.