The purpose of the California High School Performance Reports is to provide a means for the public to judge a school's progress towards: (1) implementing the educational reforms outlined in California State Legislature Senate Bill 813; (2) upgrading the quality of its instructional program; and (3) improving student achievement. This paper discusses the technical inadequacy of the reports. The most serious defects of the performance reports are that they do not measure what they purport to measure and the data provide no information for judging school quality. The quality indicators are uninterpretable, can be misleading, and are useless for determining how well schools are meeting the mandates of the reform legislation. Although the reports offer two standards against which the public is supposed to measure school quality (the state targets and comparison band percentile ranks) these standards have no relationship to the stated aims of the High School Accountability Program (HSAP). A review of these two indicators leads to the conclusion that each is an inappropriate measure of schooling. The need for HSAP to publish data related to worthwhile educational goals based upon a consensual definition of school excellence is emphasized. (PN)