We all want to have a real impact on how well our students do at school. After all, it’s why most of us became teachers in the first place.
The success of your aspirations as a teacher depends upon the impact you have on your students’ results.
Passion for evaluating impact is the single most critical lever for instructional excellence.
But do you really know how much impact you are having?
Many of us don’t. Given this, it is impossible to truly evaluate how effective our teaching has been. As a result, we make decisions about our teaching based on fads, personal beliefs, and mandates from above.
Even teachers who want to measure their impact find it hard to do so, simply because they don’t know how.
This article will show you how to use effect size to know thy impact by measuring the effect you have on your students.
What Is Effect Size? A Way to Know Thy Impact
Effect size is a measure of progress, not a measure of achievement. It describes how much a student has improved not how they did in comparison to other students within the class.
Imagine this scenario. Harry achieved a yellow belt in karate. When he graded, he skipped orange belt and went straight to green belt. His sister, Samantha was also learning karate. She was already a green belt, and after grading she became a blue belt.
Samantha achieved a higher belt than her brother Harry. However, her brother made more progress. The karate instructor knows the impact she had on each student, and can adjust her approach accordingly.
While effect size is not measured in belts, the principle is the same. A teacher who had a 0.8 effect on their students had far more impact than a teacher who had a 0.3 effect.
Furthermore, we know that the typical teacher has a 0.4 effect on their students over a single year. Therefore, if you have an effect that is:
- Less than 0.4, you are having a lower than average impact on your kids’ result
- More than 0.4, you having a higher than average impact on your students’ learning
How To Calculate Effect Size
In order to calculate an effect size, you need to know where your students are at the start of a unit and then compare this to where they got to at the end of the unit. The distance travelled shows you the progress they made.
A Tool To Help You Know Thy Impact
If statistics and mathematical formula aren’t your thing – you can save a lot of time using John Hattie’s Progress vs Achievement Tool. It uses Microsoft Excel. All you have to do is put your students’ names in, with their scores beside their name. It does the rest for you.
A Note On Assessment Tasks
The formula uses the words ‘tests’, and in many cases tests are an appropriate form of assessment.
However, there are also times when other sorts of tasks are more appropriate, such as when marking a piece of writing. You can still measure effect size using many of these tasks.
Still, there may be other situations where effect-size is not the best measure of progress. For example, when you want to check for understanding during a lesson. Effect-size is a potent tool in your assessment toolbox, but it is just one tool.