After six years of studying the instructional methods used by “highly skilled” teachers in 16 countries, we now know the most effective way to teach math.

There isn’t one.

“Common events in one classroom are novel in another and some of our most entrenched assumptions are challenged by practices in other countries,” he says. “For example, a good teacher in Sweden does different things to a good teacher in Hong Kong – but they are good in different ways.”

The teachers had developed different approaches to beginning and ending lessons, what tasks to pose and when and how, and monitoring and assistant learning. These were influenced by resources, class sizes and, particularly, culture (such as how adults interact with children, how they give criticism and praise).

Amazing. The best teachers vary their approach based on the many factors that make each school – each classroom – different from others.

Of course, there are some common strategies that can be shared among all teachers.

But the essence of bad teaching is to follow the same script with every student, in every class. The same is true for assessing them all the same way.

math, teaching, methods