DIFFERENTIAL ABILITY SCALES - Pearson Clinical Ability Scales. Differential Ability Scales. ... Quantitative

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    DIFFERENTIAL ABILITY SCALESDIFFERENTIAL

    ABILITY SCALES

    AuthorColin D. Elliott, Ph.D.

  • Copyright by The Psychological Corporation. All rights reserved.

    DifferentialAbility ScalesDifferentialAbility Scales

    A differential measurement of distinctive abilities that yields a profile of strengths and weaknesses.

    A differential measurement of distinctive abilities that yields a profile of strengths and weaknesses.

  • Copyright by The Psychological Corporation. All rights reserved.

    DifferentialAbility ScalesDifferentialAbility Scales

    Sattler (2001) Review of the DAS1. Good validity 2. High reliabilities3. Excellent standardization4. Good administration procedures5. Good administrative guidelines and test

    materials6. Helpful scoring criteria

    Sattler (2001) Review of the DAS1. Good validity 2. High reliabilities3. Excellent standardization4. Good administration procedures5. Good administrative guidelines and test

    materials6. Helpful scoring criteria

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    DifferentialAbility ScalesDifferentialAbility Scales

    7. GCA based on high g loadings8. Special Nonverbal Composite9. Efficiency10. Good Handbook11. Co-normed with achievement tests (link to

    WIAT II is coming soon)

    7. GCA based on high g loadings8. Special Nonverbal Composite9. Efficiency10. Good Handbook11. Co-normed with achievement tests (link to

    WIAT II is coming soon)

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    DifferentialAbility ScalesDifferential

    Ability Scales

    Age Range: 2:6 to 17:11 years

    Preschool Cognitive BatterySchool-Age Cognitive BatteryAchievement Battery

    Age Range: 2:6 to 17:11 years

    Preschool Cognitive BatterySchool-Age Cognitive BatteryAchievement Battery

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    Structure of the DAS Cognitive Battery

    Structure of the DAS Cognitive Battery

    Ages2:6 3:5GCA Only

    Ages3:6 5:11

    GCA and 2 Clusters

    Ages6:0 17:11

    GCA and 3 Clusters

    General Conceptual

    Ability

    Verbal Ability

    Nonverbal Ability

    Verbal Ability

    Nonverbal Reasoning

    Ability

    Spatial Ability

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    Average Administration Times

    Average Administration Times

    65 minutes50 minutes15-20 minutes

    All Cognitive SubtestsGeneral Conceptual AbilityAchievement Subtests

    Ages 6:0 - 17:11

    65 minutes40 minutes

    All Cognitive SubtestsGeneral Conceptual Ability

    Ages 3:6 - 5:11

    35 minutes25 minutes

    All Cognitive SubtestsGeneral Conceptual Ability

    Ages 2:6 to 3:6

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    Special Nonverbal Composite

    Special Nonverbal Composite

    Pattern ConstructionRecall of DesignsMatricesSequential and Quantitative Reasoning

    Ages 6:00 17:11

    CopyingPattern ConstructionPicture Similarities

    Ages 3:6 5:11

    Block BuildingPicture Similarities

    Ages 2:6 3:6

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    Preschool Ages 2:6-3:5 Subtests

    Preschool Ages 2:6-3:5 Subtests

    Core Cognitive TestsBlock BuildingVerbal ComprehensionPicture SimilaritiesNaming Vocabulary

    Core Cognitive TestsBlock BuildingVerbal ComprehensionPicture SimilaritiesNaming Vocabulary

    Diagnostic TestsRecall of DigitsRecognition of Pictures

    Diagnostic TestsRecall of DigitsRecognition of Pictures

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    Preschool Ages 3:6-5:11 Subtests

    Preschool Ages 3:6-5:11 Subtests

    Core Cognitive TestsVerbal ComprehensionPicture SimilaritiesNaming VocabularyPattern ConstructionCopyingEarly Number Concepts

    Core Cognitive TestsVerbal ComprehensionPicture SimilaritiesNaming VocabularyPattern ConstructionCopyingEarly Number Concepts

    Diagnostic TestsRecall of DigitsRecognition of PicturesBlock BuildingMatching Letter-Like Forms*Recall of Objects**

    Diagnostic TestsRecall of DigitsRecognition of PicturesBlock BuildingMatching Letter-Like Forms*Recall of Objects**

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    School-Age 6:0 17:11 Subtests

    School-Age 6:0 17:11 Subtests

    Core Cognitive TestsPattern ConstructionWord DefinitionsSimilaritiesMatricesSequential and Quantitative ReasoningRecall of Designs

    Core Cognitive TestsPattern ConstructionWord DefinitionsSimilaritiesMatricesSequential and Quantitative ReasoningRecall of Designs

    Diagnostic TestsRecall of DesignsRecognition of Pictures*Recall of ObjectsSpeed of Information Processing

    * Ages 6:0 7:11 only

    Diagnostic TestsRecall of DesignsRecognition of Pictures*Recall of ObjectsSpeed of Information Processing

    * Ages 6:0 7:11 only

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    Age RangesAge Ranges

    The usual age range refers to the ages at which the subtests are ordinarily administered.The extended age range refers to the ages at

    which the subtests also can be administered for diagnostic purposes.The out-of-level age range refers to the ages

    at which the subtests can be administered to examinees who function at unusually high or low levels for their age.

    The usual age range refers to the ages at which the subtests are ordinarily administered.The extended age range refers to the ages at

    which the subtests also can be administered for diagnostic purposes.The out-of-level age range refers to the ages

    at which the subtests can be administered to examinees who function at unusually high or low levels for their age.

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    Efficient Administration Procedures

    Efficient Administration Procedures

    Tailoring items to the childs abilityStarting point and Decision point based on age.If performance on initial set is too high or too low, extend to harder or easier items.Convert performance on items taken to ability score (does not rely on basals and ceilings)

    Tailoring items to the childs abilityStarting point and Decision point based on age.If performance on initial set is too high or too low, extend to harder or easier items.Convert performance on items taken to ability score (does not rely on basals and ceilings)

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    DAS SCORESDAS SCORES

    Standard Scores (Mean=100, SD=15)Percentile ScoresGrade Equivalents

    Achievement Composite

    Standard Score (Mean=100, SD=15)General Conceptual Ability (GCA)

    Standard Score (Mean=100, SD=15)Age Equivalent Scores

    Verbal Ability ClusterNonverbal Ability ClusterNonverbal Reasoning Ability ClusterSpatial Ability Cluster

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    Calculation of Scores

    Calculation of Scores

    Raw scores are converted to ability scores, which are based on IRT.

    Ability scores are converted to T scores within the examinees age group.

    T scores are summed to obtain cluster scores.

    Cluster scores are summed to obtain the GCA.

    Raw scores are converted to ability scores, which are based on IRT.

    Ability scores are converted to T scores within the examinees age group.

    T scores are summed to obtain cluster scores.

    Cluster scores are summed to obtain the GCA.

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    Score RangesScore Ranges

    GCA: 44 to 175(downward extension to 25)

    Cluster Scores: 43 to 162

    GCA: 44 to 175(downward extension to 25)

    Cluster Scores: 43 to 162

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    Out-of-Level Testing

    Out-of-Level Testing

    Full norms for many subtests and composites beyond the usual age range.

    Useful for testing developmentally delayed and gifted

    Full norms for many subtests and composites beyond the usual age range.

    Useful for testing developmentally delayed and gifted

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    Standardization Sample

    Standardization Sample

    3475 Children

    350 per year Ages 2:6 to 4:11 years200 per year Ages 5:0 to 17:11 years

    3475 Children

    350 per year Ages 2:6 to 4:11 years200 per year Ages 5:0 to 17:11 years

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    Fairness of ResultsFairness of Results

    Extensive Bias AnalysisOversampling of African/American and Hispanic Children (100+ cases from each group/item)

    Extensive Bias AnalysisOversampling of African/American and Hispanic Children (100+ cases from each group/item)

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    DAS ValidityDAS Validity

    Satisfactory concurrent validity. GCA correlates highly with other measures of intelligence (WISC III, SB IV)Good construct validity.

    (Sattler, 2001)

    Satisfactory concurrent validity. GCA correlates highly with other measures of intelligence (WISC III, SB IV)Good construct validity.

    (Sattler, 2001)

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    DAS ReliabilityDAS Reliability

    Excellent reliability (for example, average internal consistency reliability coefficients for the GCA are .90, .94, .95 for lower Preschool Level,

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