science policy Hattie

Do education policy makers believe in science?

Legislative sessions in many states closed recently with new or updated laws that directly contradict volumes of robust scientific research.

How Popular Policies Measure on the Effectiveness Scale

Additionally, effect isn’t cumulative. We can’t take a 0.4 factor, add a 0.2, and get a classroom with an effect of 0.6. It’s more like an average. Combine a 0.2 factor with a 0.4 and you’ll end up with something closer to 0.3. (That’s an oversimplification, but works for the gist.) So if we’re considering ways to improve achievement, we should discard anything that doesn’t measure up to what we’re already doing. If it’s not more positive than our average, we actually slow student growth. So how do popular policies rate on the scale? Here’s a sample:

Low effect   Average effect   High effect
Class size 0.21 Phonics 0.52 Collective teacher efficacy 1.57
Charter schools 0.07 Small group instruction 0.47 Response to intervention 1.07
Retention -0.17 Goal setting 0.40 Frequent feedback 0.73

Class Size

Most states have regulations around class size, so the $37 billion Florida has invested in class size reduction makes intuitive sense. If teachers have fewer students, each one will get more attention and they’ll make more progress. However, more isn’t necessarily better. If a little math fact drill ‘n’ kill is good, a lot is great, right?

All other things being equal, without changing what activities are happening in the classroom, a 30 student class won’t achieve any more than a 20 student class. If we want students to benefit from reduced class size, we need to offer schools more professional development so teachers can use their newly freed up time to improve their practice.

Charter Schools

What about charter schools? Federal budget proposals would increase charter-specific spending to $500 million tax dollars for the next fiscal year. Champions of “school choice” advocate for  charter schools to increase local education options and point to data reporting that charter schools work, but a 0.07 effect (marginally better than zero growth) doesn’t support their argument. If these schools aren’t measurably better than what we’re already doing, instead of re-allocating public funds to build what might be duplicative infrastructure, we should look for more impactful ways to change our existing schools.


Retention laws, however, are arguably the most damaging policy we enact.

Sixteen states and Washington D.C. have mandatory retention laws for students who are not reading at grade level by the end of the third grade. Eight more states allow but don’t require it. Advocates for retention talk about “social promotion” preventing students from receiving the additional supports they require to improve their literacy skills, but research tells us there’s almost nothing we can do that would be more harmful to a student’s progress.  We know that students who are held back don’t learn more than their promoted peers—in fact, they often learn less both in their retention year and in the long-term.

If we continue to enact policies that haven’t improved student achievement and learning the way they’re promoted to, we won’t see the dramatic effects to education we would by focusing on driving the changes pinpointed by Hattie to be the most effective.

More effective drivers may be frequent feedback or response to intervention. Science doesn’t lie, and legislatures across state lines will continue to stunt our progress if they don’t consider the distinct scientific evidence and let that influence policy. For now, we’re left asking the question, “Do education policy makers believe in science?”

Latest posts by eSchool Media Contributors (see all)

Want to share a great resource? Let us know at