This study assessed how some key measurement issues were considered in the context of a specific integrated reading and writing assessments conducted at each of seven grade levels in the Riverside (California) Unified School District. Data are reported for the following parameters: (1) test reliability; (2) test validity; (3) scoring; (4) scaling; (5) weighting; and (6) equating. Issues are considered in light of validity criteria proposed by R. L. Linn (1991). In general, reliability and validity reported for the assessment are encouraging, although test-retest reliability estimates and generalizability coefficients would add to evidence for the generalizability of the assessment. Evidence is also presented from teacher surveys that supports the meaningfulness of the assessment and positive impacts on instructional practices. Efficiency and cost effectiveness are also considered acceptable. Recommendations are given for alternative assessment methods. It is concluded that instruction might be best served by allowing schools to use performance assessment results in a more informal manner, with more subjective judgments about the process. Twelve tables present study data. (SLD)