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What do Test Scores Really Mean? Rebecca Mann [email protected]

What do Test Scores Really Mean? Rebecca Mann [email protected]

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Page 1: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

What do Test Scores Really Mean?

Rebecca Mann

[email protected]

Page 2: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu
Page 3: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Why test?School effectivenessDetermine what students know

and can doCompare student achievement to

achievement of similar studentsCompare student ability level

and achievement

Page 4: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Norm vs. Criterion Referenced

Norm referenced•Comparing a person's score against the scores of a

similar group who have taken the same exam, called the "norming group."

•Examples•California Achievement Test (CAT)

•Comprehensive Test of Basic Skills (CTBS) - "Terra Nova“

•Iowa Test of Basic Skills (ITBS)

•Metropolitan Achievement Test (MAT)

•WISC

•Stanford-Binet

•Bell Curve – all students cannot be above average!

Page 5: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Norm vs. Criterion Referenced

Criterion referenced• Measure how well a person has learned a specific

body of knowledge and skills

• Examples• ISTEP and most state exams

• ITBS and Terra Nova

• Driver’s License test

• Content area placement exam (Algebra placement test)

• Do not compare student to student

Page 6: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

… Wait until KINDERGARTEN

… THIS WEEK WE TOOK A TEST TO SEE IF WE’RE READY FOR THE TEST THAT TESTS OUR TEST SKILLS…

Page 7: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Ability vs. Achievement Ability Test

•Measure of cognitive ability

•Child’s ability to learn Achievement Test

•Measure of what an individual has learned There may be a discrepancy between

ability and achievement scores•Underachievement

•Learning Disability

Page 8: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Individual vs. Group Ability Tests Individual intelligence tests are

considered the most accurate measure of intelligence•Wechsler Intelligence Scale for Children (WISC-

IV)

•Wechsler Preschool & Primary Scale of Intelligence (WPPSI-III),

•Stanford Binet (SB-5)

•Woodcock-Johnson III (WJ-III) cognitive Individual IQ tests must be given by a

school or counseling psychologist.

Page 9: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Individual vs. Group Ability Tests Group intelligence tests are commonly

used as screening measures Common group intelligence tests

•Otis-Lennon School Ability Test - OLSAT

•Cognitive Abilities Test – CogAT IQ scores are not given on group tests

Page 10: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Group Achievement Tests

Criterion-referencedTypically on grade level content,

therefore difficult to know the level of mastery for a gifted child

Grade-level achievement tests are only a measure of basic skills

You cannot compare standard scores on achievement tests to IQ scores. 

Page 11: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Will this beon the test?

Page 12: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Ceiling The highest level of performance or

score that a test can reliably measure WISC-IV = 160 Stanford-Binet IV = 165 CogAT = 150 OLSAT = 150

Page 13: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Standard Deviation a statistical measure of spread One standard deviation is the range which

includes 65% of all scores, two standard deviations includes 95% of all scores

Page 14: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

68%96%

Page 15: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

From Get Off My Brain, by Randy McCutcheon, illustrated by Pete Wagner

Page 16: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Types of ScoresRawPercentile RanksGrade Equivalent ScoresStandard Scale Scores

Page 17: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Raw Score

The number of items a student answers correctly

Allow students to be ranked, but they do not allow you to compare students

Page 18: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Percentile RankA percentile rank indicates the percentage

of students in the same age or grade group whose scores fall below the score obtained by a particular student.

99 is the highest percentile rank possible. 50 is considered average Deals with percentage of persons not

percentage of items

Page 19: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Grade Equivalent ScoreMost misinterpreted test score If a 4th grader received a 7th grade

equivalent score on a 4th grade reading achievement test, it DOES NOT mean the child is ready for 7th grade material. It means the child reads 4th grade material as well as the average 7th grader reads 4th grade material.

What is the test assessing???

Page 20: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Age Equivalent ScoreFrequently misinterpreted If a 10 year old received a 15 year

old age equivalent score on a 4th grade reading achievement test, it DOES NOT mean the child is ready to tackle 10th grade material. It means the child reads material intended for 10 year olds as well as the average 15 year old reads it.

Page 21: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Stanine Stanine is short for standard nine. The name

comes from the fact that stanine scores range from a low of 1 to a high of 9. For instance, a stanine score of • 1, 2, or 3 is below average• 4, 5, or 6 is average• 7, 8, or 9 is above average

The stanine scale is a normalized standard score scale consisting of nine broad levels designated by the numbers one through nine.

Stanines are provided for both age and grade groups.

Page 22: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Standard Age Score• Raw Scores are converted to SAS

based on chronological age• Used for interpretation purposes

•Scale scores allow comparison of students

• Somewhat akin to an IQ score• Uses means and standard deviation• Mean = 100

Page 23: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

68%96%

Page 24: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Standard scores 130 and above Very Superior 120-129 Superior 110-119 High Average 90-109 Average 80-89 Low Average 70-79 Borderline 69 and below Impaired (Mentally Retarded

range)

Page 25: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Relationship Between CogAT Scores

Stanine 1 2 3 4 5 6 7 8 9

Percentile Rank

1-4 5-11 12-23 24-40 41-59 60-76 77-88 89-95 96-99

SAS 70 80 90 100 110 120 130

Standard Deviation

-2 0 +2

Page 26: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Standard Measure of Error The range inside which an individual

subject's future scores are expected to fall, based on her current score

The score +/- the standard measure of error is the estimated range in which the actual score lies

130 +/- 5 means that the child’s true score is somewhere between 125 and 135

Page 27: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

Confidence Interval Using the standard measure of error A range of values that indicates where the true

score is likely to fall Often expressed in 68%, 90%, or 95% Such as: We can say with 68% confidence that

a student’s true score is within this range. The higher the confidence (95 instead of 68),

the wider the range of scores

Page 28: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

K-BIT

Page 29: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

WISC-IV – 5rd grade boy Verbal Comprehension: 150 Perceptual Reasoning: 146 Working Memory: 97 Processing Speed: 88 Full Scale IQ: 127

Page 30: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

WISC-IV – 3rd grade boy Verbal Comprehension: 110 Perceptual Reasoning: 137 Working Memory: 135 Processing Speed: 112 Full Scale IQ: 130

Page 31: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

5th 3rd

Verbal Comprehension: 150 110Perceptual Reasoning: 146 137Working Memory: 97 135Processing Speed: 88 112Full Scale IQ: 127 130

Page 32: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu
Page 33: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu
Page 34: What do Test Scores Really Mean? Rebecca Mann rlmann@purdue.edu

http://www.hoagiesgifted.org/tests.htm http://achieve.org/files/indiana_ISTEP_0.

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