By Jay Mathews
Thursday, March 29, 2007
Dear Extra Credit:
Not so fast. Steve Shapiro's data on homework completed and quarterly grades [Extra Credit, Fairfax Extra, March 22] don't prove that doing homework results in better grades. The data show correlation, not causation. It could be that the ability to get better grades results in higher homework completion rates. The data cannot distinguish between cause and effect.
It may be that students who get better grades are more conscientious about their responsibilities.
There may be many reasons why students receiving poorer grades do less homework: It takes them too long; they have no interest in the subject; or they lack motivation and discipline.
Furthermore, a straight-line relationship between homework completed and quarterly grades explains only about 60 percent of the variation in the data.
The pitfalls in drawing conclusions using data from uncontrolled experiments are not widely recognized, even by the mathematically literate.
A controlled experiment would have to introduce some degree of randomness to the percentage of homework completed, maybe by assigning different amounts of homework to students.
Of course, few parents and teachers would agree to participate in such an experiment.
Ferd Neider
Vienna
Dear Extra Credit:
Steve Shapiro, a math teacher at Annandale High School, drew an unwarranted conclusion from his data about homework completion and quarterly grades in his letter -- a conclusion with which you agreed.
It makes a great deal of sense to say that if students don't do their homework, their grades probably will be lower. It is quite another thing to say that doing homework increases learning.
A common learning situation is for students to sit in class and go through a lesson and then be asked to complete homework on their own. One of these scenarios generally results:
1. The student understood the material at least reasonably well and doing the homework could reinforce the concepts. Doing the homework also could be a waste of time for students if they had no trouble understanding the lesson.
2. The student understood the material somewhat during class. In this case, doing homework could provide benefits for students, forcing them to work through problems and possibly use their notes or other valid resources, such as classmates or family members, to help them out.
Doing homework also could simply confuse these students more as they try to decipher the homework without the supervision of the teacher. (This problem is especially evident in math for high school students because their parents generally are unable to help them with the increasingly complex problems.)
3. The student did not understand the material in class. Homework then, at worst, proves to these students that they are incapable. At best, these students will go for extra help from their teachers. I think it is safe to say that for many students, repetitive failure to understand homework causes them to abandon any attempt to do it or ask for extra help.
And there lies the problem. Yes, if students don't do homework, their grades are likely to go down. Mr. Shapiro didn't provide statistics on the grades his low-achieving students earned on the homework they did complete, just homework completion compared with quarterly grades. [Editor's note: He did, but the data on the grades were taken out of the chart because the editor thought they complicated the issue.]
Doing more homework problems covering concepts a student doesn't understand to begin with isn't going to cause the student to somehow start understanding them. Additional or different teaching is needed, not more homework.
Often the students do get that additional help, but let's be clear that it is the additional tutoring that causes the increase in learning, not more homework.
Like Mr. Shapiro, I believe homework can be useful. But I also believe much of what is given to students as homework is either a waste of time or counterproductive. All kinds of research have supported this.
Until we rethink how we are educating our students and don't simply recycle the "just do your homework" mantra, we will continue to get the same results: some students performing wonderfully, others lagging far behind.
Bretton Zinger
Chantilly High School journalism and film studies teacher
Uh-oh. Another C-minus in journalism for me.
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