I'm sure every teacher has shaken their heads at one time or another and thought or said "Why don't those students do their homework?" Although that is usually a rhetorical question that is quickly forgotten once planning the warmer for the next lesson kicks in, I think looking at the real answers can be the start of a useful process that can lead to that being true much less often than it was.
Why students might not do their homework and what you can do aboutit:
1. It's boring
Unless you were a very square kid indeed, I'm sure you understand this feeling! You might also remember the things that made homework something you would happily spend extra time on: getting other parts of your brain working (artistic activities, logic puzzles, using your imagination); project work; competition; working as a team; finding out something new about the world; or an excuse to interact with people (e.g. interviewing a family member). All of these can fairly easily be brought into EFL homework.
2. They don't understand the instructions/ what to do
A common excuse this one, even when it is just an excuse... Tactics to take away that excuse include writing the instructions on the board, doing one example of each exercise in class, pre-teaching the language that is used in the workbook instructions and doing a similar exercise right at the end of the class.
3. It's too difficult
Another one that is very often said and quite often true! Reactions include giving them hints on where they can go for help (e.g. the grammar reference at the back of the students' book), giving mixed up answers, giving an easier task for the lower level students to do, doing exactly the same exercise in class without letting them take away a copy and letting them do it half from memory for homework, or advising them that they should work together in study groups.
4. It's too easy
Less common to hear this one, but even if it is okay for most people that means it must be too easy for at least one person! Easy ways to make homework more challenging include taking away the multiple choice answers to turn it into a gap fill, giving the homework for the same language point from a different workbook, telling them to do it within a certain time limit or asking them to do the exercise orally before they write their answers down.
5. They could understand the language, but couldn't think of any ideas (e.g. arguments for and against or a storyline)
You could try brainstorming ideas at the end of the class, teaching them brainstorming and other creative techniques, or giving optional ideas they can use (but somewhere that takes a bit of effort to get to so everyone tries to be creative first)
6. It's not their priority, e.g. because it doesn't involve speaking
They may just be right on this one! You can ask them their priorities and design the homework around that, get them to write down what they did instead in a study diary or share it with the class, or give tasks that can be adapted for different students ("Write a phone conversation or an email in which..."
7. They just forgot/ forgot exactly what they had to do
Such is human nature, especially when your subconscious is telling you it is something you don't want to do. Aside from using the tips here to make it so interesting that it is at the front of their mind all the time, ways to avoid this include having a totally fixed routine and schedule for homework, giving them a written schedule for all the homework at the beginning of each month or term, having the homework written up somewhere they can easily check it like the school notice board or blog, and checking that each person has marked the right exercise with the date it must be finished by
8. They don't find time/ have bad time management
Occasions where it seems you have no option but to fix someone's personality come up surprisingly often in language teaching, but that doesn't make it any easier to do. Options for this problem include doing a lesson on how they use their time and time management, finding out when they do have time and designing the homework to fit in with it (e.g. a recording they can do in their car or a compact self-study book such as a graded reader they can do standing up on the train), telling them how long each exercise should take, or even asking them to write the time and date when they are going to do it rather than the date it must be done by in their workbooks.
9. It's a minor rebellion
This could be a symptom of problems with you or teachers more generally that will demand a very flexible response to that particular student or group of students- for example; some students could actually be rebelling because they think you aren't strict enough! In these cases, someone outside the situation like someone observing your class is probably the best person to ask.
10. They don't see the point/ don't think it will improve their English
Again, there is always a chance that they are right about whatever the publishers have thrown in at the last minute to fill up that page of the workbook. Ways to make sure this is not the case include giving them options on what they do, doing a needs analysis and designing it to fit in with the skills they think they need, doing a classroom activity a second time after they have done the homework and show how them it is easier because of what they have learnt, and telling them how likely the language will be to come up on the test or in their lives,
11. Doing homework seems childish
It can be difficult to tackle this complaint in a class where other students want more fun, but possibilities include giving them whole pieces of writing such as emails rather than gap fills (and certainly not word searches!), giving them homework which is connected to or similar to their work, giving them the answer key to check their own answers, and giving them the choice of several pieces of homework.
12. They lack a place where they can do it in peace and quiet
Tell them to move house. Only joking! Possibilities include giving them the listenings in a different format so they can listen on headphones, having an area in the school where they can do it, giving them homework that can be broken into 5 minute segments to do when and where they can, and a class discussion on where other students find time and space to do it.
13. They lack equipment (e.g. a CD player)
This is as much a problem in developed countries as developing ones- in that case because TEFL schools are the only places still using cassettes! Approaches include suggesting ways the same homework can be done without the equipment, (e.g. reading tapescript), offer the equipment in your Self- Access Centre, telling them how they can obtain the recording etc in a different format, and having a few copies in a different format or a few pieces of the necessary equipment that the students can circulate amongst themselves.
14. They have their own self-study materials or habits which they prefer
Again, they could be right on this one. You can use that fact by setting them a self-study schedule using their own methods with suggestions on making it tie in with the textbook syllabus.
A few more tips on giving homework
1. Always show that you notice if it is done or not, even if it is a quick glance over the shoulder and "Good" or a slight frown
2. Recycle the language of the homework in class, e.g. checking it straight off and using that language in the warmer for the rest of the class
3. Combine routine and variation- get them very similar homework until they get used to it, then throw in something more unusual before they get bored
4. If you've done your own homework, e.g. when studying the language of the country you are living in, share that fact with the students if they haven't done theirs
5. Give rewards- praise, making it easier to score points in the games in class if they have completed the homework, skipping the next homework if they were the only one to do the last one, setting the teacher homework etc.