I wanted to comment on the fact that some say that an MIS should be able to provide all the features needed to analyze assessment data.
From my experience in the dutch secondary education, I've seen that the MISs in Holland provide pretty similar features to those in England. However, the dutch systems all lack proper analysis tools. The hammer and saw analogy that Mike uses is quite appropriate. Most SIMs are created to be an administration system, not an multi-data source analysis system. To get to the data you need, without spending hours and hours of Excel craftmanship, is not always as easy as it might seem. And the usage of custom Excel sheets (from very small to supersheets (even pink ones ) is much more common than durable solutions that are built for proper data analysis.