Initial validation of the Schedule of Growing Skills (SGS)

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

2. Content • Background • Validation process • Step one • Step two • Conclusions

3. 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.

4. 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%.

5. 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).

6. 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.

7. SGS Profile Form

8. 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.

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

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

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

12. Subscale comparisons

13. 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

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

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

16. Results: Step one Aim 2: Concurrent validity with GMDS

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

18. Results: Step two Aim 1: Concurrent validity with ASQ

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

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

21. Thank you for listening Diolch am wrando Any questions??