Data analyses can affect teachers’ instructional strategies.  They can do so mainly be helping teachers understand what their students are and are not learning.  However, these analyses can only really help if teachers use a particular strategy exclusively before they assess their students over a given set of material.

If a teacher uses a certain strategy exclusively to teach a set of material, they can then assess their students and see how well the students learned the material.  By looking at the data, they can see if the students learned.  If the students learned well, it is likely that the strategies were good ones.   The teacher might then teach the next unit using a different strategy.  When the results from that unit’s assessment are analyzed, the teacher can make inferences about that strategy.

In practice, this can be difficult.  Teachers do not usually teach in only one way, making it difficult to know which strategies worked.  It is also hard to know how well students would have learned certain materials if taught in a different way, thus making it harder to draw inferences from the data.

That said, it is at least possible for data analyses to inform teaching practices.