9.4 Conclusions

This section compared the D-scores estimated from the DDI administered to three different groups of children.

We found that

• The D-score by age plot showed a positive, curved relationship with age in all three studies;
• Children born very preterm or with very low birth weight had similar development to reference children when their age was corrected for early birth;
• A relatively small subset of children born in Togo had extremely low D-scores, not found in the Netherlands, likely the result of underlying neuropathology, severe underweight or severe stunting;
• On average, children from Togo seemed to have faster development during the first two years, especially in motor development, though there may be issues with reporting bias.

All in all, these findings support the usefulness and validity of the D-score as an informative summary of child development during their first two years of life.