WJIII:  Woodcock-Johnson Tests of Achievement

The Woodcock-Johnson Tests of Achievement is a widely-used, comprehensive collection of tests measuring level of achievement in reading, mathematics, written language, and knowledge. Currently the most recent edition is the IIIrd (WJIII). Individual tests are organized into clusters which measure different aspects of each subject area. These tests can be scored based on age norms or grade norms.

The Reading tests are organized into three clusters. The Broad Reading Cluster is considered the most general measure of reading achievement, and is composed of Letter-Word Identification and Passage Comprehension. The Basic Reading Skills Cluster measures sight vocabulary and the ability to apply phonic and structural analysis skills. It is composed of Letter-Word Identification and Word Attack. The Reading Comprehension Cluster measures comprehension of single words (Reading Vocabulary) and of words in context of a passage (Passage Comprehension).

The Mathematics tests are organized into three clusters. The Broad Mathematics Cluster measures skill in performing written calculations (Calculation) and in analyzing and solving practical word problems (Applied Problems). The Basic Mathematics Skills Cluster measures computational skill (Calculation) and knowledge of mathematical concepts and vocabulary (Quantitative Concepts). The Mathematics Reasoning Cluster is composed only of the Applied Problems test.

The Written Language tests are organized into three clusters. The Broad Written Language Cluster measures production of single-word responses (Dictation) and production of sentences in context (Writing Samples). On the Basic Writing Skills Cluster measures single-word responses (Dictation) and identification of errors in spelling, punctuation, capitalization, and usage (Proofing). The Written Expression Cluster measures production of increasingly complex sentences in context (Writing Samples) and timed production of simple sentences according to a general rule (Writing Fluency).

The Broad Knowledge Cluster is composed of the Science, Social Studies, and Humanities tests, and measures knowledge of general content areas, rather than specific skills.

The WJIII Achievement tests can also be used with the coordinated Woodcock-Johnson III Tests of Cognitive Ability.

Discrepancy Analysis

The WJ III is especially useful for identifying and documenting ability/achievement discrepancies and intra-ability discrepancies. The ability/achievement discrepancy is the most commonly used method of evaluating an individual's eligibility for special programs. Professionals can obtain ability/achievement discrepancies by administering both the WJ III Tests of Cognitive Abilities and the WJ III Tests of Achievement. The WJ III provides three types of ability/achievement discrepancies - general intellectual ability to achievement, predicted achievement to achievement, and oral language to achievement.

The oral language to achievement discrepancy is a new measure offered only in the WJ III. For the first time, professionals can calculate an ability/achievement discrepancy using only the achievement battery. The Oral Language-Extended cluster, which used to be in the cognitive battery, can now be used as the "ability" score and compared to a subject's achievement. score. This measure is particularly useful for reading and other oral language professionals.

The WJ III also provides intra-ability discrepancies, which include intra-achievement discrepancies, intra-cognitive discrepancies, and intra-individual discrepancies. Information gathered from intra-ability discrepancies helps professionals to determine an individual's strengths and weaknesses, diagnose and document language and learning disabilties, and make intervention plans.

The intra-individual discrepancy procedure has several advantages over traditional aptitude/achievement discrepancy procedures. It provides a more comprehensive evaluation because examiners can analyze a variety of scores across cognitive and achievement clusters. The intra-achievement discrepancy procedure examines the difference between an individual's achievement score in a particular area with a prediction estimated based on an average of all other achievement areas to help professionals to identify learning disabilities, pinpoint specific problems, and choose the most appropriate intervention for an individual. The procedure is also particulary useful for identifying learning disabilities early, before a child fails in school.


Most of the WJ III tests show strong reliabilities of .80 or higher; several are .90 or higher. The WJ III interpretive plan is based on cluster interpretation. The WJ III clusters show strong reliabilities, most at .90 or higher. The reliability characteristics of the WJ III meet or exceed basic standards for both individual placement and programming decisions..