Highest effect sizes in the Math Classroom

As teachers we always believe we know what is right for students in the classroom.  We work hard, practice our skill, and care about kids.  However, if you take the time to look from classroom it is apparent we go about our skill in different ways.  This is fine for the most part but as more studies are done, and the results repeat themselves it becomes obvious there is a science to our art called education.  The studies have been done irregardless of grade level and there is some background to understand the numbers.

     - An effect size greater than 0.4 has a positive effect.
     - An effect size between 0.5 - 0.6..."your crazy not to do it."
     - and an effect size of 0.7 needs to beg the question "why are you not doing this already."

As it turns out, the teacher staple that smaller class sizes help instruction holds no merit.  Good teachers succeed in any class size.  The statistical effect for class size is 0.27.  This correlates to showing no positive effect at all.  Sorry...

On the contrary, if you would like to start off simple get your kids up and around.  The simple act of physical movement shows an effect size of 0.54 (your crazy not to do it).  The trick is, how can we structure the time with our students that gets them up and moving?

The three highest effect sizes should come as little to no surprise if you have been engaging in professional development.  

1. Spaced vs. Mass Practice (0.71)  -  Mass practice is all students do 1 - ???.  Spaced is differentiated.  Some students do #1, ...  Other students do a different set or an entirely different practice depending on their level of understanding or areas of interest.  By doing this practice it opens the door to knowing your students well enough to differentiate.  
2. Assessment as a Process of Formative Feedback (0.75) - Everyone knows what formative assessment is.  However, lots of teachers (math in particular) are still stuck on the summative assessment being the be all end all of student learning.  Challenge yourself to consider when learning is completed and what our job is as teachers?  If my sole job is to rate/rank my students then I am drastically selling short my abilities.  We are hired to inspire learning and engage students in a manner that causes them to dig deeper and do things they don't always feel comfortable doing.  Something called learning.  Formative assessment gives me the information necessary to know exactly where my students are at and determine the instruction necessary to get them to where we need them to be.
3. Classroom Discourse (0.82) - Getting a discussion going in your classroom about the topic you are working on has an effect size higher than the category labeled "why are you not doing this already."  To often as math teachers we feel teaching is us talking.  In reality, the more we talk the less they learn.  Clearly there are those topics we need to describe.  The challenge is how you can get a deep discussion going about the topic.  These discussions, if done properly by letting the students do the talking will greatly increase the depth of your topic while also performing a large degree of the formative assessment needed to understand where your students are at.

The basic gist that everyone needs to hear is simple.  Do not "try" these classroom strategies.  DO THEM.  The better we do them the higher the effect.