Appropriate time for feedback and criticism

During the State Cup, I was the assistant referee on an u13 boys game. The final was 12-1. The head coach of the losing team spent most of his time venting to an assistant coach directly behind me. In the first half, one of his players took a corner kick and the ball sailed out of bounds. The coach was very upset. He said that the same thing had happened five times last game but he had let it go because they had a lop-sided win. He added that he was not going to let it go anymore, and he was going to get on them at halftime.When is the appropriate time to "get on" players about a mistake? Many coaches take the same approach. When things are going good, they overlook mistakes. Then, when the same mistakes occur in a poor performance, they get upset.This is focusing on the result, rather than the process. If the mistake is a problem in a loss, it should have been a problem in a win. Furthermore, discussing the mistakes after a win takes away the blame, and demonstrates that the team still has areas to improve, regardless of the score.If "getting on" the players at halftime meant that the coach was going to rant and rave about the mistake, what is the purpose? Essentially, the purpose is to make the coach feel better. Instead, what is causing this frequently occurring mistake? Is there a technique issue? Are the players aiming for an inappropriate target? Do the players need to account for the wind? Should the players try a left-footed kicked on the right side to have an in-swining corner kick?I am not a soccer expert, so there are likely other reasons or explanations. Aren't these the areas that the coach would want to address when "getting on" the players about the mistake?I assume that the players are not kicking the ball out of bounds on purpose. Therefore, the mistake stems from an inability to perform the skill or a lack of understanding about the skill. When providing feedback to the players, this is what should be addressed. Simply yelling at the players and telling them that they're making a mistake will not help the players improve or change their future execution; it will simply make the coach feel better, and maybe feel like he is coaching.By Brian McCormick, PhDDirector of Coaching, Playmakers Basketball Development LeagueAuthor, The 21st Century Basketball Practice and Fake Fundamentals