One of the ways I think about data, and also the purpose of teacher evaluation in general, is whether the information presenting itself is useful for decision-making. Ultimately, that decision-making is what much of policy is about. Are we making the best decisions possible, as a teacher, as a school leader, as a district staffer, certainly as a bureaucrat tasked with coaxing policy-making aspirations into in-reality improvements.
How you process all this brand new information is an important part of the decisions you end up making. You can see my post on the EDGEucator blog about the decision-making implications of the question "Compared to what?"