How well does the focus on stu­dent per­for­mance lev­els for account­abil­i­ty, with the School Per­for­mance Score (SPS) and asso­ci­at­ed let­ter grades, cap­ture schools’ con­tri­bu­tion to stu­dent learn­ing? Specif­i­cal­ly, how does the SPS com­pare to ​“val­ue-added” mea­sures for schools that account for dif­fer­ences in stu­dents’ past per­for­mance? Could this reliance on the SPS actu­al­ly reduce over­all achieve­ment com­pared with alter­na­tive mea­sures? For char­ter school autho­riz­ers, should this influ­ence the reau­tho­riza­tion process?