Increasingly, states and teacher education programs are establishing minimum requirements for cooperating teachers' (CTs') years of experience or tenure. Undergirding these policies is an assumption that to effectively mentor preservice teachers (PSTs), CTs must themselves be instructionally effective. We test this assumption using statewide…

Papay (2011) noticed that teacher value-added measures (VAMs) from a statistical model using the most common pre/post testing timeframe--current-year spring relative to previous spring (SS)--are essentially unrelated to those same teachers' VAMs when instead using next-fall relative to current-fall (FF). This is concerning since this choice--made…