The problem with the stern voice is it can also be taken as a teasing voice by some kids and especially if there are no further consequences. The idea behind the stern voice is that it serves as the final warning to kids to shape up or face the penalties so they generally do as they are told at the stern voice phase. The little ones know it as a game that means very little. Stern voice with action is much more effective and not necessarily a time out which is detached from the event. A child that hits or tosses something or whatever can be held by the arms, stern voice right in their face with only a few words of what is not acceptable as you move and plunk the child down in a spot away from where they did the event - even just a couple feet. It is the physical swooping in getting in their face and forcing them to sit that is the effective part. Depending on what happened they are not allowed to move till you have finished dealing with the event - comforting another child, picking up the tossed item and putting up out of child's reach etc.