The school year has just begun and already parents are bracing themselves for nightly battles to get their kids to finish their homework. Parents hate homework almost as much as their kids do. One parent recently posted a note her daughter's second grade teacher had written declaring that there would be no homework that school year and parents around the web practically tripped over themselves to register their support.

I wrote recently about the potential benefits of homework and how in many cases, those positives are outweighed by the fact that extra busy work takes up time that kids could be spending doing things that might really improve their performance in school — things like having dinner with their families, exercising or getting a good night's sleep.

The Organization for Economic Cooperation and Development (OECD) keeps track of things like students performances around the world and compares data based on economic information as well as learning policies.

One such policy is the amount of time that students are expected to spend on homework. Homework policies around the world vary widely. In Finland, high school students may spend around three hours per week completing homework assignments. In the U.S., homework time is doubled. Yet Finnish students lead the world in global scores for math and science. They come in third among 57 countries for scores in reading. The U.S., on the other hand, hovers in the middle of the charts in all three disciplines.

Despite the siren song of homework proponents who insist that homework increases student performance, this OECD graph shows that this is rarely the case. In fact, this comparison of students within each country shows how piling on the homework can actually be detrimental to student's scores.

OECD PISA 2006 Database As this graph shows, in many countries, the more time students spend on homework, the worse they perform in school. (Photo: OECD)

It seems the world has caught on to this idea that less is more when it comes to homework. In its latest report, the OECD found that the average number of hours that students spent doing homework decreased from 2003 to 2012 in almost every country around the world, except for the U.S. American students have seen an increase in weekly homework, yet test scores have remained stagnant over the 10-year study period.

So what do countries like Finland know about homework that we Americans don't? The answer is not a simple one. There are many factors that affect an educational system — from poverty rates to parental leave policies to the availability of preschools — and they can't all be quantified in neat little charts. In addition to its minimalism when it comes to homework, Finland also has subsidized daycare, generous maternity leave policies and free health care for students. All of these policies affect student grades as much as or maybe even more so than their low teacher-student ratios or the fact that teaching is one of the most highly respected occupations in the country.

One major difference that is evident between Finnish and American homework policies is that of content. In the U.S., homework — particularly in elementary and middle schools — consists of worksheets that reward memorization over rational thinking. But content is king when it comes to homework in Finland. Students aren't assigned homework unless it plays an integral role in what they are learning. This changes the way that both teachers and students view the assignments. Teachers in Finland are also actively encouraged to alter assignments based on the needs of individual students.

The point isn't that homework is evil. It's that we are doing it wrong. And if we really want students to benefit from extra hours spent hitting the books, it makes sense to take a closer look at the countries that are doing it right.