Initial validation of the Schedule of Growing Skills (SGS) Margiad Elen Williams Bangor University

Content Background Validation process Step one Step two Conclusions

Background Screening tools are used to identify children with possible developmental delay to enable subsequent more rigorous assessment. Quick, inexpensive, and easy to use. Should be as accurate as possible.

American Academy for Pediatrics (2006) Published recommended psychometric criteria that all screening tools should meet. Sensitivity – proportion of correctly identified children in need of further assessment. Specificity – proportion of correctly identified children who are developing typically. Both need to be at least 70%.

The SGS in Wales Welsh Assembly Government introduced Flying Start (FS) Initiative. SGS chosen as the developmental screening tool to evaluate FS Initiative. Problems with scoring identified during IY Toddler trial (Hutchings et al., 2011).

Problems with SGS scoring Windows of assessment vary. Score highest item within scale regardless of performance on other items. Cannot compare between groups or across time. Problems can be solved by developing way of scoring to yield a Developmental Quotient (DQ) score.

SGS Profile Form

Aims To validate both the original and new DQ way of scoring the SGS. Two step validation process. Use of two data sets, the RCT of the IY Toddler programme and MRes project comparing the SGS and GMDS.

Step one Aim 1: Estimate appropriate cut- off for new SGS scoring method Aim 2: Determine concurrent validity of both SGS scoring methods against GMDS Step two Aim 1: Determine concurrent validity of both SGS scoring methods against Ages and Stages Questionnaire (ASQ)

Step one: Sample & Measures Participants 39 children Mean age 31 months 61% male Measures Griffiths Mental Development Scales (GMDS) Schedule of Growing Skills (SGS)

Step two: Sample & Measures Participants 94 children Mean age 22 months 61% male Measures Ages and Stages Questionnaire (ASQ) Schedule of Growing Skills (SGS)

Subscale comparisons Griffiths Mental Development Scales (GMDS) Schedule of Growing Skills (SGS) Ages and Stages Questionnaire (ASQ) LocomotorGross motor Performance & Eye-Hand Coordination (fine motor) Manipulative & Visual (fine motor) Fine motor LanguageHearing, Speech, & Language Communication Personal-SocialInteractive & Self-care

Results: Step one Aim 1: Establishing cut-off point Receiver Operating Characteristic (ROC) Curves Explored three potential cut-off points: - DQ < 90 - DQ < 85 - DQ < 80

Results: Step one SGS cut-offAUCSensitivitySpecificity DQ < DQ < DQ < Most accurate cut-off is DQ < 85. Both sensitivity and specificity levels > 70% Aim 1: Establishing cut-off point

Results: Step one Aim 2: Concurrent validity with GMDS Calculated: - Sensitivity - Specificity - Over-referral rates - Under-referral rates

Results: Step one Aim 2: Concurrent validity with GMDS Development area SGS scoringSensitivity (%) Specificity (%) Over- referrals (%) Under- referrals (%) LocomotorOriginal New (DQ < 85) Personal-SocialOriginal New (DQ < 85) LanguageOriginal New (DQ < 85) Fine motorOriginal New (DQ < 85) OverallOriginal New (DQ < 85)

Results: Step two Aim 1: Concurrent validity with ASQ Calculated: - Sensitivity - Specificity - Over-referral rates - Under-referral rates

Results: Step two Aim 1: Concurrent validity with ASQ Development area SGS scoringSensitivity (%) Specificity (%) Over- referrals (%) Under- referrals (%) LocomotorOriginal New (DQ < 85) LanguageOriginal New (DQ < 85) Fine motorOriginal New (DQ < 85) OverallOriginal New (DQ < 85)

Discussion 1 New SGS scoring method shows increased concurrent validity. Better sensitivity, comparable specificity, higher over-referrals, lower under-referrals.

Limitations Small sample sizes GMDS training Implications Increased detection rates Greater use in clinical practice and research Discussion 2

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