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How is the Woodcock-Johnson Scored?

Three types of statistics or scores are generated by the Woodcock Johnson-IV

  • level of development
  • comparison with peers
  • degree of proficiency

Level of Development

Age equivalents

An age equivalent (AE) or age score, reflects the child’s performance in terms of age level in the norming sample at which the average score is the same as the child’s score. For example, if a child named Sam is 8 years old and receives an AE of 12.1 on a particular test, the correct interpretation would be, “Test results indicate that Sam’s performance on this test is comparable to that of an average 12 year old.”

Grade equivalent

A grade equivalent (GE), or grade score, likewise reflects the child’s performance in terms of the grade level of the norming sample at which the average score is the same as the child’s raw score. For example, if a child named Rita, a 7th grader, received a GE of 6.5 on the Reading Fluency test, the correct interpretation would be, “Rita is a 7th grader who currently performs at the mid-sixth grade level in reading fluency.”

Comparison with Peers

Standard Score

The standard score (SS) on the WJ-IV describes a child’s performance relative to the average performance of the comparison group. The scale is the same as the IQ test. In other words, the average standard score is 100 with a standard deviation of 15. For example, if a child named John had a standard score of 85 in the calculation test, he would be functioning in the low average range for that particular skill.

Percentile Rank

A percentile rank (PR) describes a child’s relative standing to his or her peers on a scale of 1 – 100. Thus, a percentile rank of 6 would indicate that only 6 children out of a hundred in a comparison group (similar age and education level) would score as low or lower.

Relationship Between Standard Score, Percentile Rank, and Classification

Score Range Percentile Rank Range Classification
131 and above 98 to 99.9 Very Superior
121 to 130 92 to 97 Superior
111 to 120 76 to 91 High Average
90 to 110 25 to 75 Average
80 to 89 9 to 24 Low Average
70 to 79 3 to 8 Low
69 and below 0.1 to 2 Very Low

Degree of Proficiency

Relative Proficiency Index (RPI) This statistic is particularly useful in predicting the child’s adjustment to a particular academic program. The RPI predicts a child’s level of proficiency on tasks that typical age or grade peer would perform with 90% proficiency. For example, suppose a particular child generated a RPI of 55/90 on the calculation test. This means that, on similar math tasks, the child would demonstrate 55% proficiency, whereas the same age or grade peer would demonstrate 90% proficiency. Please note the denominator in the RPI is always 90 (representing 90% efficiency on the test or task) whereas the numerator varies from 0 – 100 and represents how proficient the particular child tested is on that task. Table two presents the interpretations of RPI scores.

Interpretation of RPI Scores

Reported RPIs Functionality Implications for Academic Achievement
100/90 Very Advanced Extremely Easy
98/90 to 100/90 Advanced Very Easy
95/90 Within Normal Limits to Advanced Easy
82/90 to 95/90 Within Normal Limits Manageable
67/90 to 82/90 Mildly Impaired to Within Normal Limits Difficult
24/90 to 67/90 Mildly Impaired Very Difficult
3/90 to 24/90 Moderately Impaired Extremely Difficult
0/90 to 3/90 Severely Impaired Impossible

AE = Age Equivalent

The child’s performance on a particular task is presented in terms of the age level of an average performance on that task.

GE = Grade Equivalent

The child’s performance on a particular task is presented in terms of the grade level of an average performance on that task.

Easy to Diff = Easy to difficult

This statistic provides the age range of what the child would find easy to very difficult on a particular academic task.

RPI = Relative Proficiency Index

This statistic provides the level of proficiency on a particular task. SS = Standard Score This statistic compares the child’s performance to others of his age (average standard score is 100).

Woodcock-Johnson® Tests of Achievement® (W-J-III® and WJ-IV ®) is a registered trademark of Riverside Publishing, a Houghton Mifflin Company, or their affiliate(s), or their licensors. TestingMom.com is not affiliated with nor related to Houghton Mifflin Company or its affiliates (“Houghton Mifflin”). Houghton Mifflin does not sponsor or endorse any TestingMom.com product, nor have TestingMom.com products or services been reviewed, certified, or approved by Houghton Mifflin. Trademarks referring to specific test providers are used by TestingMom.com for nominative purposes only and such trademarks are solely the property of their respective owners.

Tell Us Your Experiences

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8 Responses

Tom Grenga says:

My son just received his results and I am confused about the PR and PR Classification.
Stats. Male, 14 and 4 months. Grade 8.8.
ACADEMIC KNOWLEGE GE=>17.9 Easy to Diff 11.8 >17.9 AE >30 PR Classification High Average PR 86
Does this mean 86 % of the children tested who are 14-4 in grade 8.8 have similar results?

TestingMom.com says:

Hi Tom – please email us at help @ testing mom.com – we can give you better direction or the scoring for the WJ-III

Pat says:

Most schools refuse to give the parents the Age and Grade Equivalent scores.

Amy says:

My child was considered average or slightly below or above average in all areas. However, the report says that of the math problems completed had correct answers but he still only was “average”. Are they looking at the number of the total problems completed in the time alotted? Would this be what makes him “average”. They boy is flunking math so I can’t believe the report. To confound things the assessor cannot provide samples from the protocols because she shredded them right after she made the report. It sounds sketchy to me. Is it true that the writing parts of the test are subjective?

Amy says:

To clarify my comment above: ALL the answers to the math problems were correct. I left out the word “all”.

Diane says:

I would like to express my deep concern about the word “impossible” used in the scoring of the test. My autistic grandson was subjected to this test in second grade and to see the word “impossible” used to describe an autistic child’s ability is appalling. Our family was traumatized yet again and thrust back into the grieving process as a result of reading the word “impossible” over and over again. I would like to know how I can appeal to the authors of this test to remove this language from the test. I think it is a word that should NEVER be used to describe any child’s ability let alone an autistic child. If there is ONE thing we do know about austitic children,it is that we don’t know what they are capable of!

Diane Gundersen says:

I posted a comment about my concern for the language used in the Woodstock-Johnson test. I am specifically opposed to the word “impossible” used to describe a child’s ability. This language has NO place in our assessments. What happened to my post about my experience with this test?

Diane Gundersen says:

I did see my original comment after inquiring about it with a second post. I want any information available to appeal to the authors of this test to remove the word “impossible” from the language. Thanks in advance for any assistance you can provide.