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Wechsler Nonverbal Wechsler Nonverbal Scale of Ability Scale of Ability
Jack Naglieri, PhDJack Naglieri, PhDProfessor of PsychologyProfessor of Psychology4400 University Drive, MSN 2C64400 University Drive, MSN 2C6George Mason UniversityGeorge Mason UniversityFairfax, VA 22030Fairfax, VA [email protected]@gmu.edu
•• The WNV is a nonverbal measure of The WNV is a nonverbal measure of general ability measured using tests general ability measured using tests that that – involve different demands– do not contain verbal content (e.g.,
Vocabulary) – do not require the examinee to speak– use pictorial directions
•• WNV was specifically created for:WNV was specifically created for:– Individuals from diverse linguistic groups– Those who have limited language skills– Hard of hearing or deaf individuals– Individuals with language disorders– Identification of gifted children from
•• The test is intended for fair assessment of The test is intended for fair assessment of culturally and linguistically diverse culturally and linguistically diverse populations from many countriespopulations from many countries
•• Standardized in the US and CanadaStandardized in the US and Canada•• For ages 4:0 For ages 4:0 –– 21:1121:11•• Yields a Full Scale and subtest scoresYields a Full Scale and subtest scores•• Innovative administration formatInnovative administration format•• Full (45 minute) and brief (20 minute) Full (45 minute) and brief (20 minute)
versions versions and softwareand software included in every kitincluded in every kit
•• The WNV can be given to a wide variety of The WNV can be given to a wide variety of individuals making it ideal for students who individuals making it ideal for students who speak many languagesspeak many languages
•• Minimal adaptation needed for use in Minimal adaptation needed for use in different countries or with those from different countries or with those from different countriesdifferent countries
•• Meets IDEA 2004 requirements for reliable Meets IDEA 2004 requirements for reliable and valid nondiscriminatory assessmentand valid nondiscriminatory assessment
•• The WNV uses a new method for informing The WNV uses a new method for informing the examinee of the demands of the test the examinee of the demands of the test ––Pictorial Directions Pictorial Directions (patent pending)(patent pending)
•• Examinees are shown a series of pictures Examinees are shown a series of pictures that illustrate what he or she has to dothat illustrate what he or she has to do
•• The Pictorial Directions include gestures by The Pictorial Directions include gestures by the examiner that draw the examineethe examiner that draw the examinee’’s s attention to the correspondence between attention to the correspondence between the directions and the stimuli on the tablethe directions and the stimuli on the table
•• Verbal directions in several languages are Verbal directions in several languages are provided in the Administration Manualprovided in the Administration Manual
•• Provide help instruction allows the Provide help instruction allows the examiner to interact with the examinee in examiner to interact with the examinee in any manner to ensure that the demands of any manner to ensure that the demands of the task are understood. This is not the task are understood. This is not teaching how to do the task, but instead teaching how to do the task, but instead explaining what is required.explaining what is required.
•• Only for Older ExamineesOnly for Older Examinees•• Adapted from WISCAdapted from WISC--IV IntegratedIV Integrated•• Forward and BackwardsForward and Backwards
•• Step 2. Subtest AnalysisStep 2. Subtest Analysis– Compute the mean of the four T scores– Subtract the mean from each T score– Compare the differences to the value in
Table B.1– Differences that are equal to or greater
than the value in Table B.1 are significant•• Negative values are WeaknessesNegative values are Weaknesses•• Positive values are StrengthsPositive values are Strengths
Subtests:Subtests:Matrices 57Coding 44Spatial Span 38Picture Arr 52mean T = 48
Lucy’s scores on individual subtests indicate a relative strength on Matrices, a subtest requiring reasoning with spatial designs (Matrices = 57 vs. Mean = 48), and a relative weakness on Spatial Span, a subtest requiring visual-spatial memory (Spatial Span = 38 vs. Mean =
48). Additionally, Lucy’s Spatial Span score is below average and the discrepancy between Lucy’s Spatial Span T score and her mean T score was unusual (occurring in only about 6% of the normative sample).
•• Spatial Span Forward and Backward each Spatial Span Forward and Backward each yield a T score yield a T score – These scores can be compared using Table C.2
•• InterventionIntervention– Based on subtest scores– Manual example of Lucy
•• She performed poorly in relation to her overall She performed poorly in relation to her overall subtest mean and in relation to her peerssubtest mean and in relation to her peers
–– This suggests that it may be useful to consider the This suggests that it may be useful to consider the role memory difficulties may play in academic role memory difficulties may play in academic taskstasks
–– Also consider other evidence of memory statusAlso consider other evidence of memory status»» Teacher and parent reportsTeacher and parent reports»» Other dataOther data
•• Lucy performed poorly in relation to her mean Lucy performed poorly in relation to her mean andand her peers on Spatial Span her peers on Spatial Span – consider the role memory difficulties may play in
academic tasks – especially if there are parent or teacher concerns
about Lucy remembering information – The same hypothesis could be associated with
•• RecognitionRecognition•• Coding if the examinee did not appear to remember the Coding if the examinee did not appear to remember the
correspondence between shapes and numberscorrespondence between shapes and numbers
•• Use chunking or mnemonic methods for tasks Use chunking or mnemonic methods for tasks that demand recall of informationthat demand recall of information
•• There is much empirical support for these There is much empirical support for these techniques for improving memory (techniques for improving memory (MastropieriMastropieri& Scruggs, 2006; & Scruggs, 2006; MinskoffMinskoff & & AllsoppAllsopp, 2003). , 2003).
•• To aid in the selection and communication of To aid in the selection and communication of these interventions to parents and teachers use these interventions to parents and teachers use Naglieri and Pickering (2003) handoutsNaglieri and Pickering (2003) handouts
•• If scores on Matrices, Picture If scores on Matrices, Picture Arrangement, and Object Assembly are Arrangement, and Object Assembly are significantly lower than the mean and significantly lower than the mean and below Averagebelow Average
•• These subtests require an examinee to These subtests require an examinee to relate parts of the items into a coherent relate parts of the items into a coherent whole (described by Naglieri [1999] as whole (described by Naglieri [1999] as involving simultaneous processing) involving simultaneous processing)
•• Methods such as Graphic Organizers Methods such as Graphic Organizers and Story Maps (and Story Maps (MastropieriMastropieri & & Scruggs, 2006; Scruggs, 2006; MinskoffMinskoff & & AllsoppAllsopp, , 2003; Naglieri & Pickering,2003) may 2003; Naglieri & Pickering,2003) may helphelp
•• These methods provide the student These methods provide the student with ways of working with information with ways of working with information that must be arranged as a conceptual that must be arranged as a conceptual wholewhole
Table 5.15. WNV and WPPSITable 5.15. WNV and WPPSI––III III WNVWNV
FSIQFSIQ MeanMean SDSD NNFull Scale Score 4Full Scale Score 4 .71.71 101.9101.9 11.711.7 5656Full Scale Score 2Full Scale Score 2 .67.67 101.4101.4 11.911.9 5656WPPSIWPPSI--IIIIIIMeanMean 101.7101.7SDSD 9.99.9NN 5656Notes.Notes. All correlations were computed separately for each order of admAll correlations were computed separately for each order of administration in inistration in
counterbalance design and corrected for the variability of the Wcounterbalance design and corrected for the variability of the WNV standardization NV standardization sample (Guilford & sample (Guilford & FruchterFruchter, 1978). The weighted average across both orders was , 1978). The weighted average across both orders was obtained with Fisher's z. The Means are the average of the two oobtained with Fisher's z. The Means are the average of the two orders.rders.
•• 41 examinees ages 541 examinees ages 5––21 identified as 21 identified as giftedgifted
•• examinees had to have existing scores examinees had to have existing scores on a standardized measure of cognitive on a standardized measure of cognitive ability that were at least 130ability that were at least 130
•• 51 non51 non--institutionalized examinees ages 4institutionalized examinees ages 4––2121– Diagnosed with mild mental retardation and/or IQ
scores 2–3 SDs below the mean (i.e., 55 ≤ FSIQ ≤70).
•• The WNV was also administered to 31 nonThe WNV was also administered to 31 non--institutionalized examinees, ages 5institutionalized examinees, ages 5––21, who 21, who were previouslywere previously– diagnosed with moderate mental retardation and/or
IQ scores 3–4 SDs below the mean (i.e., 40 ≤ FSIQ ≤ 55).
•• 36 examinees36 examinees•• ages 4ages 4––1717•• 63% were identified with a Mixed 63% were identified with a Mixed
ReceptiveReceptive--Expressive Language Disorder Expressive Language Disorder according to according to DSMDSM––IVIV––TR TR criteria, criteria,
•• 37% were identified with an Expressive 37% were identified with an Expressive Language Disorder according to Language Disorder according to DSMDSM––IVIV––TR TR criteria.criteria.
&English Language LearnersEnglish Language Learners
•• The WNV was administered to 55 examinees, The WNV was administered to 55 examinees, ages 8ages 8––21, who met the criteria for 21, who met the criteria for classification as English Language Learners. classification as English Language Learners. – native language was not English– primary language they spoke was not English– language other than English spoken at home– parents had resided in the US less than 6 years
•• examinees selected based on their lack of ever examinees selected based on their lack of ever having heard spoken languagehaving heard spoken language– examinees must not have been able to hear tones
after the age of 18 months– must not lip read– must not use cued speech (i.e., they must have
routine discourse by some means of communicating other than spoken language)
– severe to profound deafness (hearing loss measured with dB, Pure Tone Average greater than or equal to 55).
•• Examinees have had exposure to spoken Examinees have had exposure to spoken language, either through hearing or lip readinglanguage, either through hearing or lip reading
•• The group could have a unilateral or bilateral The group could have a unilateral or bilateral hearing loss or deafnesshearing loss or deafness
•• age of onset of their inability to hear could be age of onset of their inability to hear could be any age. any age.
•• The examinee could have cochlear implants.The examinee could have cochlear implants.•• And the following additional criteria: And the following additional criteria:
– No disability or impairment other than being deaf or hard of hearing
•• The WNVThe WNV– Provides an innovative method for
administration– Has excellent reliability– Strong validity evidence– Easy to interpret– Has instructional implications– Can be given to a wide age range
•• Yoakum & Yoakum & YerkesYerkes(1920) summarized (1920) summarized the methods used the methods used by the military to by the military to classify people classify people from many from many backgrounds by backgrounds by mental capacitymental capacity
This test, This test, developed developed by by KempfKempfand Knox and Knox was used at was used at Ellis Island Ellis Island in the Early in the Early 1900s1900s
•• ““The ManikinThe Manikin”” test test appeared in the appeared in the ArmyArmy’’s testing s testing program as a program as a performance or performance or nonverbal testnonverbal test
•• David Wechsler was a David Wechsler was a military examiner who military examiner who worked at Fort Logan worked at Fort Logan Texas in the early Texas in the early 1900s1900s
•• He administered the He administered the Army tests described Army tests described by Yoakum & by Yoakum & YerkesYerkes(1920) (1920)
•• These nonverbal These nonverbal tests have a long tests have a long history as measures history as measures of general abilityof general ability
•• Nonverbal tests Nonverbal tests have been shown to have been shown to be effective be effective measures of general measures of general abilityability
•• OverOver--representation of minorities in representation of minorities in special education special education (Naglieri & (Naglieri & RojahnRojahn, 2000), 2000)– Too many Blacks and Hispanics are
identified as having mental retardation •• UnderUnder--representation of minorities in representation of minorities in
•• MessickMessick (1995) argued that the validity (1995) argued that the validity of instruments must be questioned if of instruments must be questioned if they contribute to overrepresentation they contribute to overrepresentation of minorities in special education of minorities in special education classes for children with mental classes for children with mental retardation (Oswald, retardation (Oswald, CouthinoCouthino, Best, & , Best, & Singh, 1999). Singh, 1999).
•• Ban the use of IQ testsBan the use of IQ tests•• Change the definition of intelligenceChange the definition of intelligence•• Increase fair assessment of children Increase fair assessment of children
using measures that do not use verbal using measures that do not use verbal and achievement laden measures of and achievement laden measures of ““abilityability””
•• The child reads a sentence and selects The child reads a sentence and selects an option that completes the meaningan option that completes the meaningBirds ____ in the sky”
A nestA nest C swimC swimB flyB fly D floatD float
•• This is This is alsoalso a vocabulary testa vocabulary test•• And, these questions require readingAnd, these questions require reading•• What level of reading is required?What level of reading is required?
•• CogATCogAT Form D Level 6 is intended for Form D Level 6 is intended for children in grades 5 and 6children in grades 5 and 6
•• The Sentence Completion test The Sentence Completion test readability grade level is 6.1 (range 3.7 readability grade level is 6.1 (range 3.7 -- 10.4) using Flesch10.4) using Flesch--Kincaid readability Kincaid readability formulaformula
•• 80% of the items have readability of 80% of the items have readability of grade 5 or more!grade 5 or more!
One item on the a One item on the a verbal verbal Comprehension Comprehension subtest is like subtest is like this:this:What should you do if you see smoke in your house?
“A boy had twelve books and sold five. How many books did he have left?”
Peter counted seventeen lily pads at the pond. There were frogs sitting on five of the lily pads, and the rest were empty. How many lily pads were empty?(a) 22 (b) 13 (c) 12
Quantitative Ability or Quantitative Ability or Achievement?Achievement?
•• How much money would How much money would these drinks and snacks these drinks and snacks cost?cost?
•• If you these two balls and If you these two balls and you had this much money, you had this much money, how much money would how much money would you have left?you have left?
Quantitative Ability or Quantitative Ability or Achievement?Achievement?
•• The sandbox is eight feet The sandbox is eight feet long, four feet wide, and one long, four feet wide, and one foot deep. How many cubic foot deep. How many cubic feet would be needed to fill feet would be needed to fill it?it?
•• How much sand is needed How much sand is needed to fill this sandbox half to fill this sandbox half way?way?
•• Poverty or low SES negatively affects test Poverty or low SES negatively affects test scores because of limited enrichment at scores because of limited enrichment at homehome– high poverty is correlated with low test scores
because of issues associated with educational enrichment at home and at school
– many students receive low test scores because of limited opportunity to learn
•• MminoritiesMminorities are penalized on traditional tests of are penalized on traditional tests of intelligence and denied access to gifted education intelligence and denied access to gifted education programs and services programs and services
•• Such denial of access is common when ability tests are Such denial of access is common when ability tests are highly verbal and achievement orientedhighly verbal and achievement oriented
•• Bracken and Naglieri (2003) state Bracken and Naglieri (2003) state – “general intelligence tests with verbal
content and nonverbal content measure essentially the same construct as general ability tests that are entirely nonverbal”(p. 247)
– Both types measure general ability•• one measures general ability with varying one measures general ability with varying
content (verbal, quantitative, and nonverbal) content (verbal, quantitative, and nonverbal) and the other uses nonverbal tests and the other uses nonverbal tests
Median rMedian r .59.59 .63.63 .60.60NN 1,2841,284 24,10824,108 8888
WISCWISC--3 data from WIAT Manual Table C.1 ages 63 data from WIAT Manual Table C.1 ages 6--1616NNAT data from Naglieri (1997) NNAT Technical ManualNNAT data from Naglieri (1997) NNAT Technical ManualWNV data from Wechsler & Naglieri (2006) Technical ManualWNV data from Wechsler & Naglieri (2006) Technical Manual
•• WechslerWechsler’’s view of intelligence as not that s view of intelligence as not that verbal an nonverbal were two types of verbal an nonverbal were two types of intelligenceintelligence
•• nonverbal tests helped minimize the overnonverbal tests helped minimize the over--diagnosing of retardation caused by diagnosing of retardation caused by intelligence tests that were too verbal intelligence tests that were too verbal
•• verbal and performance tests as equally verbal and performance tests as equally valid measures of intelligence and valid measures of intelligence and
•• He criticized the labeling of performance He criticized the labeling of performance tests as measures of special abilitiestests as measures of special abilities
•• General ability has been General ability has been measured since 1939 with the measured since 1939 with the Wechsler ScalesWechsler Scales
•• These tests included many These tests included many subtests that differed in their subtests that differed in their content and requirements content and requirements
•• Individual subtest scores and Individual subtest scores and an overall composite score (a an overall composite score (a Full Scale score) were used to Full Scale score) were used to reflect general abilityreflect general ability
•• Subtests were aggregated into Subtests were aggregated into composites based on the composites based on the content of the subtestscontent of the subtests
•• The Wechsler test were selected to measure general The Wechsler test were selected to measure general ability with content that variesability with content that varies– Some require knowledge of words and comprehension of
verbal relationships– others require recall of numbered sequences or reasoning with
arithmetic or spatial stimuli •• “…“… the attributes and factors of intelligence, like the the attributes and factors of intelligence, like the
elementary particles in physics, have at once collective elementary particles in physics, have at once collective and individual propertiesand individual properties”” (Wechsler, 1975, p. 138)(Wechsler, 1975, p. 138)
•• The subtests form a cohesive whole represented in the The subtests form a cohesive whole represented in the Full Scale, which reflects the concept of general ability.Full Scale, which reflects the concept of general ability.
•• Tests may differ in their content or specific Tests may differ in their content or specific demands but still measure the concept of general demands but still measure the concept of general intelligenceintelligence
•• Spearman called this the Spearman called this the ““indifference of the indifference of the indicatorindicator”” (1927, p. 197) (1927, p. 197)
•• ““the subtests are different measures of the subtests are different measures of intelligence, not measures of different kinds of intelligence, not measures of different kinds of intelligenceintelligence”” (Wechsler, 1958, p. 64)(Wechsler, 1958, p. 64)
•• ““the term nonverbal refers to the content of the the term nonverbal refers to the content of the test, not a type of abilitytest, not a type of ability”” (Naglieri, 2003, p. 2)(Naglieri, 2003, p. 2)
•• The primary purpose of the WNV is to measure The primary purpose of the WNV is to measure general ability nonverballygeneral ability nonverbally
•• Tests of general ability are very similar Tests of general ability are very similar despite the difference in contentdespite the difference in content
•• Verbal or nonverbal tests are simply Verbal or nonverbal tests are simply different ways to measure general abilitydifferent ways to measure general ability
•• A nonverbal test can correlate with A nonverbal test can correlate with achievement just as well as a verbal and achievement just as well as a verbal and nonverbal testnonverbal test
•• What evidence is there that this helps with What evidence is there that this helps with fair assessment?fair assessment?
•• Samples selected from total group of Samples selected from total group of 89,600 matched on:89,600 matched on:– Gender– Region– SES– Urbanicity– Ethnicity– Public/private school setting
•• Increasing Identification of Gifted Increasing Identification of Gifted Minority Children Using the Naglieri Minority Children Using the Naglieri Nonverbal Ability Test (NNAT)Nonverbal Ability Test (NNAT)
•• Jack A. Naglieri & Donna FordJack A. Naglieri & Donna Ford•• Gifted Child Quarterly (2003)Gifted Child Quarterly (2003)
•• Sample:Sample:– 19,210 children (fall 1995 NNAT sample)– Grades K to 12 – Representative of US according to:
•• geographic regiongeographic region•• socioeconomic statussocioeconomic status•• ethnicity ethnicity •• type of school setting (public or private)type of school setting (public or private)
Comparison Comparison of Hispanic of Hispanic Children Children with and with and without without Limited Limited English English Proficiency Proficiency on the NNATon the NNAT
•• 148 Hispanic children with limited English 148 Hispanic children with limited English language proficiencylanguage proficiency– 98 % from West and South– 53 % males– 82% Low and Low Middle SES– 41% Urban settings
•• 148 Hispanic children without limited 148 Hispanic children without limited English language proficiencyEnglish language proficiency– 98 % from West and South– 53 % males– 82% Low and Low Middle SES– 41% Urban settings
% ESL183% increase 183% increase in children in children whose primary whose primary language is not language is not English English (Spanish, (Spanish, Chinese, Chinese, Korean, and Korean, and Vietnamese)Vietnamese)
•• Nonverbal tests provide a culturally Nonverbal tests provide a culturally reduced way to measure general abilityreduced way to measure general ability
•• Nonverbal tests have excellent reliability Nonverbal tests have excellent reliability and validityand validity
•• Nonverbal tests provide a way to measure Nonverbal tests provide a way to measure general ability that does not require verbal general ability that does not require verbal and quantitative skillsand quantitative skills
•• Nonverbal tests are useful for culturally and Nonverbal tests are useful for culturally and linguistically diverse populationslinguistically diverse populations
•• Strong relationships to achievementStrong relationships to achievement•• Small Race / Ethnic differencesSmall Race / Ethnic differences•• Similar identification rates for gifted Similar identification rates for gifted
childrenchildren•• Similar scores for children with limited Similar scores for children with limited