Latecomers are the bane of a teacher's life. You've prepared the mother of all lesson plans for a group activity or pairwork, tried and tested it on other willing students, streamlined it and timed it down to the last minute, only to end up sitting there waiting with a sinking feeling as the students trickle in.
Passing the time
For the first few minutes, it's perfectly reasonable to chat about the weather, the weekend, last night's match or whatever, but a moment comes when the students who were punctual start looking around as if to say "Huh?" We can extend the "courtesy time" slightly by using warmers, but however much we may believe in the power of group dynamics and the classroom as an exercise in egalitarian relationships, a moment arrives when the teacher has to show who's the boss and start the lesson proper, behind schedule and with a possible drop in the effectiveness of the activity.
Another problem with latecomers is that after you have given up on them and started the class they may stroll in some ten minutes later. You have by now set up the activity and introduced some key vocabulary or concepts. The late-arriving students leave you in a cleft stick: do you quickly summarise the situation for them, or do you leave them to sink or swim as best they can? Both solutions cause problems - the first because you lose/waste yet more time and the second because they will invariably start to ask questions about the very points you had expressly clarified at the start of the class.
Not only do latecomers - it's often the same ones every time - show a lack of respect for their classmates, but they also show a lack of respect for you as a teacher.
Students, whether children or adults, expect the teacher to be firm and to "run" the class and you would be well advised to have a quiet (or not so quiet) word with persistent offenders.
- That one-to-one class with a busy business executive
- That group of rowdy adolescent kids who aren't interested in learning English
Possibly the best way is to consider that prevention is often better than a cure. It may be worthwhile at the start of the course to lay down a few easy-to-remember rules regarding what you expect of the students - while pointing out to 'em what they can expect from you.
If the "courtesy time" is established beforehand and on the understanding that it serves a pedagogical purpose, the punctual students won't feel that they're losing out and may actually come to appreciate the extra "quality time" they get from being there before the rest of the class.
With one-to-ones the solution is simpler. Start counting your time from the agreed start time and stop the class at the agreed time. Explain to the student that you have another class starting somewhere else in ten minutes and you cannot arrive late. It tends to have an almost magical effect on the punctuality for future classes.