I attended a half day conference on various ways besides student ratings to evaluate teaching, conducted by Ron Berk. Here are his 4 take away points: 1. give explicit criteria to define what behaviors indicate effective teaching, 2. use multiple sources of evidence (peer evals, student evals, student interviews, video, etc.), 3. develop and or use best quality scales to provide the evidence, 4. create guidelines to interpret the data.
Also, linking student outcomes to teaching effectiveness is bad form. It's difficult to infer one thing (effective teaching) from another (student outcomes).