WJ IV® emphasizes the identification of strengths and weaknesses by providing comparisons within and across each of its three co-normed batteries. This complete assessment system offers the ease of use and flexibility examiners need to evaluate learning problems and improve instructional outcomes for children and adults in a way that no other assessment can. In addition to norm-referenced scores, the WJ IV provides Relative Proficiency Index (RPI) scores, which are useful for describing an examinee’s proficiency with age-level tasks. The score interpretations below are valid for the WJ IV Tests of Achievement, Tests of Cognitive Abilities, and Tests of Oral Language results.