The Bayley scale of infant development is employed as the performance indicator at 2 years corrected gestational age for high risk paediatric groups. We compare neurodevelopmental outcomes in two cohorts of VLBW infants born in 1999 to a cohort born a decade later, while also examining the challenges of direct comparison of modified scales: BSID-II (2nd edition of the scales) with Bayley-III, BSID-II was used in the 1999 group and Bayley-III for the 2009 cohort. We demonstrated that over a ten year period there was an improvement in neurodevelopmental scores achieved in VLBW babies. Overall there was almost an 8 point increase in the cognitive scores from the 2009 cohort compared with the 1999 cohort in this time period. The mean motor score increased by 6 points when comparing 1999 and 2009. However we highlight the difficulties in comparing developmental scales, and consider whether Bayley-III overestimates developmental ability?