Comparison of sample sizes and costs for use of Bayley-III compared with ASQ-3 to assess cognitive delay, given 90% power, 5% alpha and 10% control rate of delay
| Relative risk reduction | Sample size for cognitive domain (Bayley-III)* | US$ cost for Bayley-III assessments† | Sample size for cognitive domain (ASQ-3)‡ | US$ cost for ASQ-3 assessments§ | US$ difference in cost (Bayley-III minus ASQ-3) | EUR$ difference in cost (Bayley-III minus ASQ-3) |
| 0.75 | 1 474 | $1 615 504 | 2858 | $294 829 | $1 320 675 | $1 213 898 |
| 0.50 | 3 518 | $3 855 728 | 6726 | $683 563 | $3 172 165 | $2 915 886 |
| 0.25 | 14 814 | $16 236 144 | 28 038 | $2 825 419 | $13 410 725 | $12 327 273 |
*Assuming sensitivity and specificity of 90% for Bayley-III.
†Assuming Bayley-III assessment cost of USD$996 per child (EUR$917), and USD$100 per child (EUR$92) as the site payment for completion.
‡Assuming sensitivity and specificity of 65% and 89% for ASQ-3.
§Assuming 20 sites performing follow-up over 2 years, with ASQ-3 costs of USD$850 per year (EUR$781) for ASQ online subscription plus USD$0.50 per child (EUR$0.46), USD$295 per site (EUR$271) for the ASQ-3 kit, and USD$100 per child (EUR$92) as site payment for ASQ-3 completion.
ASQ-3, Ages and Stages Questionnaire V.3.