Praise and criticism serve as invaluable tools in any classroom. Both direct students to their goals, as well as to the teacher's expectations. For example, praise tells students what was done right, which means it may be repeated. Criticism tells students what was done wrong or needs work, which means it gets additional attention in the future.
For some teachers, praise comes naturally. They know just how and when to comment to students. Yet it's a skill that can be learned and used by all. In fact, it should be learned and used by all, and is every bit as important as lesson structure and reinforcement activities. Praise can get students to put in a superior performance for even a novice teacher, while his more experienced peer may struggle to get his class to rise to his expectations. Why? Because that more experienced teacher may simply not be offering effective praise.
Criticism is equally important. It goes hand in hand with praise, and provides an effective balance. Criticism can be viewed as advice or commentary on mistakes, poor performance, or whenever the class fails to meet the teacher's expectations. It is an important part of the correction and feedback process, and goes hand-in-hand with identifying mistakes and errors. The teacher shouldn't be afraid to offer criticism, provided that the problems aren't the fault of the teacher.
This last point is especially important, so it deserves a bit more expansion. There are many reasons for mistakes, too many to list here. However, let's select two as examples.
Example One: In an activity later in the lesson, most of the class continues to make mistakes with the target language. They do so because the teacher didn't provide enough activities early on for students to absorb the new grammar and vocabulary. These mistakes, then, are the fault of the teacher. There simply wasn't enough practice.
Example Two: The students don't really participate in a role play activity, and in fact just fall to chatting in their mother tongue. This happened because the teacher didn't fully and clearly explain what needed to be done. This is similarly the fault of the teacher, and it would be unfair to offer criticism here.
When offering praise and criticism, teachers should try to do the following:
1: Give genuine comments, not false ones. If students did well on an activity, then the teacher should say so. If they didn't do well, then the teacher shouldn't offer praise. It they did quite poorly, the teacher should explain what went wrong, answer any questions, and repeat the activity again.
2: Give personal comments whenever possible. The teacher can easily provide individual praise and points to work on at the end of a lesson, provided the class is relatively small. If a student needs work with pronunciation, for example, then the teacher can point out a specific problem for the student to work on before the next class meeting. If individual, personal comments aren't possible at the end of the class, then the teacher can provide quick praise or criticism as students are working on activities, provided that the comments aren't disruptive.
3: Consider praise as an opportunity to tell students what went right. The teacher should do this on a personal level whenever possible, as well as to the class as a whole. In so doing, then students know how to give a repeat performance.
4: Consider criticism as an opportunity to tell students what went wrong. They need this feedback to correct the problem. If the problem is large, such as repeated mistakes with the target language, then the teacher should allow students to repeat the activity. This builds confidence, and more likely ensures a better performance the second time around. (Read more: How to Correct: Four Ways to Handle Mistakes)
5: Make a distinction in the praise offered. If students made mistakes as they struggled through an exceptionally difficult activity, the teacher should offer praise and repeat the target language, explanation, activity, etc. If they quickly went through an easy activity, the teacher doesn't need to congratulate on a job well done. Everyone fully knows that the task was easy, which means the praise will just sound false.
6: Hold any criticism until after the activity, especially free(r) activities. This minimizes disruption. For example, if the teacher interrupts in the middle of a conversation or role play, then it's much more difficult for the students to pick up the conversation again. Of course, if students are just starting to practice the target language in an initial activity, but are also making many mistakes, then the teacher must rectify the problem. If the teacher fails to criticize and correct, then students will reinforce the mistake with more and more practice. The class will be unable to use the target language correctly.
7: Ignore the previous point if praise and criticism doesn't disrupt the activity. The teacher can provide a quick and quiet "good job" or "that's right" or "great." If said in the background, students still notice but can continue the activity. Again, if it's in the early stages of the lesson and the activities are controlled, then it's often easier and more critical to provide praise and criticism.
These are only a few ideas on praise and criticism. The teacher shouldn't be miserly with either, as long as he is sincere. In fact, sincerity may be the most important point. Students will definitely know when a task was too difficult or too easy, when they made mistakes, or when the got something right. They'll know when that praise and criticism was rightly deserved or just empty words.