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How to spot a quality screening measure

How to spot a quality screening measure. Frances Page Glascoe www.pedstest.com www.forepath.org. Standards for screening tests. Consumer Beware. Standards for screening tests. STANDARDIZATION. Large, nationally representative. Proportionate Demographics :

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How to spot a quality screening measure

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  1. How to spot a quality screening measure Frances Page Glascoe www.pedstest.com www.forepath.org

  2. Standards for screening tests Consumer Beware

  3. Standards for screening tests STANDARDIZATION Large, nationally representative Proportionate Demographics: minorities, parents’ level of education, broad geographic locations, Spanish speakers, etc. Children with disabilities ( 16% - 18% of total) Naturalistic sample

  4. Standards for screening tests RELIABILITY Inter-rater--at least 85% Test-retest--at least 85% Internal consistency > .80

  5. Standards for screening tests Validity How well does a screen actually measure what the authors claim?

  6. Good Good SCREEN DX TEST Poor Poor

  7. SCREEN DX TEST Good ? Poor ?

  8. Standards for screening tests VALIDITY Concurrent:battery should sample same domains as screen Discriminant: information on how well various kinds of problems are detected Predictive:optional but helpful for showing that items sample enduring aspects of development

  9. SCREEN Criterion Measure/Gold Standard

  10. Standards for screening tests CRITERION-RELATED VALIDITY = ACCURACY

  11. Screening sorts those who probably have problems from those who probably don’t

  12. Standards for screening tests ACCURACY SPECIFICITY = % of children without problems correctly detected (e.g., by passing, above cutoffs scores) SENSITIVITY = % of children with problems correctly detected 70% to 80% is the standard

  13. SPECIFICITY

  14. SENSITIVITY

  15. Standards for screening tests Accuracy of the Denver-II Developmental DX NO YES PASS 86 69 8 Denver-II FAIL 27 17 10 86 18 Sensitivity = 10/18 = 56% Specificity = 69/86 = 80%

  16. ACCURACY: ACROSS AGE RANGES AGE SENSITIVITY SPECIFICITY N % N % 0 - 18 mos3/4 75 66/82 80 18 mos - 3 yrs 27/34 79 117/149 79 3 - 4 1/2 yrs 26/35 74 118/165 72 4 1/2 - 8 yrs 42/57 74 172/245 70 TOTAL 98/130 75 473/641 74

  17. Rigorously Peer-reviewed

  18. Because of the enormous expense involved in standardization, reliabilty and validity research and accuracy studies, tests are expensive to create, keep current, provide translations, and to ensure that users and researchers have support and guidance. For these reasons, tests costs money and it is why few measures can be photocopied. The money, however small, you spend when purchasing measures goes to their continued development.

  19. Detection rates WITH Screening Tests 70% to 80% of children with developmental disabilities correctly identified Squiresetal, JDBP. 1996;17:420 - 427 80% to 90% of children with mental health problemscorrectlyidentified Sturner, JDBP .1991; 12: 51-64 Most over-referrals on standardized screens are children with below average development and psychosocial risk factors Glascoe, APAM. 2001;155:54-59. -

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