As a child psychologist, one of the first things I ask clients is, how much sleep is everyone in the family getting? Without a proper night's rest adults are crabby, distracted and less likely to follow through on healthy habits and goals.  Lack of sleep makes the constant problem-solving and patience needed as parents difficult to muster.  If children don't get enough sleep they are grumpy, don't eat well, and have a very hard time regulating their emotions.  Paying attention in school and staying on task is hard enough, without sleep it will feel impossible.  So when there is a concern about behavior or school performance it is important to check on quality of sleep first.