If a child has a DoodleAge of, say, 8.7 then they are working at the ability level of an average 8.7 year old. So, for a child who is eight-and-a-half and in year 4, but has a DoodleMaths Age of 8.7, they are above average.
Since the curriculum changes in 2014 (when they raised expectations for primary-aged children), a child of average ability at, say, the end of year 4, will NOT have mastered all of the end-of-year 4 objectives. By our estimates using the data we have available, only the top 25% of children realistically master all of the end-of-year 4 objectives by the end of year 4.
This means that within Doodle, you can have a child who is above average in ability (i.e. their DoodleMaths age is higher than their chronological age), but still working on mastering objectives from the year group below. That is normal and totally expected!