The most important success factor of sleep training is the self soothing amount of time an infant gets Sleep begets sleep says Dr Mark Weissbluth, but in the first 2 weeks of sleep training, the key success factor is the amount of self-soothing time an infant gets. Self-soothing occurs when your baby is able to calm down by themselves and they manage to go to sleep without external help. I’m a mother of 2 and a senior data scientist and I’ll tell you the secret of sleep training: the longer your baby spends self-soothing, the more guaranteed it is for sleep training to succeed. This is the main insight I unlocked from the sleep training data I was able to collect during the 2 sleep training cycles I have gone through with my babies. Create your own sleep training survival kit There is a lot of contradictory information about sleep training on the internet. One thing is clear from the get-go: you’re reading this post because you want to have well rested babies. I can help you create your own sleep training survival kit. (Note: I participate in the affiliate amazon program.This post may contain affiliate links from Amazon or other publishers I trust (at no extra cost to you). I may receive a small commission when you buy using my links, this helps to keep the blog alive! See disclosure for details.) I want to share with you 2 sleep recipes that worked for us: 1. Baby B was sleep trained by a sleep consultant. Assisted sleep training at 4 months old using the 1-3-5 minutes interval method, with the help of a Family Sleep Institute Consultant. 2. Baby G was sleep trained by myself (with the full support of husband). Started self-sleep training at 3 months old by allowing her to learn self-soothe. I first let her try to go to sleep by herself early in the morning (nap 1), when she was most rested. She cried quietly for 30 minutes. I had not intervened because I knew she would cry louder. This method was explained by Dr Marc Weissbluth, in his famous book: Similarities of the 2 methods: 2 weeks duration; Allow the baby to learn self-soothing: don’t pick up with baby at the first sound he/she makes; Keep a sleep log (find a free printable and more info on this here); Consider the safe recommendations of American Academy of Pediatrics Safe Sleep for preventing sudden infant death syndrome (SIDS): – Until their first birthday, babies should sleep on their backs at all times—for naps and at night. – Use a firm sleep surface. Follow a sleep routine (read more on this here); Put the baby to bed drowsy but awake (may not always be possible ); Feed only if hungry (to remove the milk – sleep association); Room setup: the nursery was at least 80% dark, temperature of 70 -72 F (21-22 C ) , white noise for the first part of the night (we used ), video and sound baby monitor on (we used BT ); Baby was properly dressed (pajamas + overnight diapers – these are great) + night bag (Slumbersac are one the best we had) Last, but not least, we cat-sleep-trained Tasty and Lestat and left them in the living room. Leave nothing to chance when trying to achieve the ultimate goal: a good night’s sleep. What was different: 1. Sleep consultants recommend starting sleep training at 4 months of age (we did this with our first born, but started at 3 months of age with our youngest baby – based on Dr Marc’s book – Healthy Sleep Habits, Happy Child, 5th Edition: A New Step-by-Step Guide for a Good Night’s Sleep). 2. We started sleep training with the night sleep in baby B’s case. This meant that we used the 1-3-5 minutes interval rule to check and console her if she cried. And yes… she cried. I personally don’t think that there are any babies that do not cry at all during sleep training. With this method, you wait and see if your baby can self soothe. 3. Baby G responded promptly to the sleep training. Normal routine would entail putting her to sleep drowsy but awake. If her immediate reaction was not good (instant crying): I would pick her up, help her calm down and try again, then leave the room and wait for her to fall asleep. Teaching your baby how to fall asleep by themselves is one of the most important life skills that they will learn. You can do this as early as 3 months of age and the result will be amazing: a happy and well rested kid, just like mine. This is a personal blog. My opinion on what I share with you is that “All models are wrong, but some are useful”. Improve the accuracy of any model I present and make it useful!