Over the years a number of systems have been developed which record coded information across a range of factors about disabilities in ethnic communities. A new coding convention has been developed to rationalise the inconsistent coding conventions of these legacy systems. The new coding convention uses codes which had different meanings in the legacy systems. This means that time series analysis gives inconsistent results, particularly showing both under and over reporting of numbers of particular disability categories. This is significant when making policies for people based on the size of the communities. To fix this would take a lot of work and expense, and management has decreed that historical systems will not be fixed, but new systems will all adopt the new coding convention. give me answer please