The following information is taken from the DfES website for parents: www.parentcentre.gov.uk
National Curriculum Levels
During Key Stages 1-3, progress in most National Curriculum subjects is assessed against eight levels. At the end of Key Stages 1, 2 and 3 the school will send you a report telling you what level your child is working at.
Children develop at different rates, but National Curriculum levels can give you an idea of how your child’s progress compares to what is typical for their age. For example, by the end of Key Stage 1, most children will have reached level 2, and by the end of Key Stage 2, most will be at level 4.
Your child's school will send you a report telling you what National Curriculum levels your child has reached in any formal assessments.
The following link is taken from the parents leaflet:
“How is your child doing at school?” The chart shows the range within which your child will be working. Click on this link to open an Adobe file: Levels