I've read both of these threads and contributed a little to the start of the first one.
Reading the early pages of this thread and pugs comments on projected outcomes at GCSE being based on KS1 or Early Years data - I think she might have been referring to Fisher Family Trust data. I don't know if this if just local to my area or nationally, but certainly it is a tool based on demographics and early results to predict what a child should score at KS2, KS3 and GCSE.
My sister who is a COG at a terrible inner-city school was distraught to see this FFT data about her sons, and that based on their relatively poor performance at KS1, the fact she is a single parent and non-university educated and lives in a C/D area - they were predicted to get D's at GCSE.
Happily for her, they have both achieved 10 A-C GCSE's, one has 3 A Levels and a 2:1 degree and the other is on-target for 3 A grade A Levels this summer.
Was it this FFT data that pugs was referring to? Because it actually does exist and if a school does better than predicted, it can affect what the LEA expect from them the following year - hence some background talk among parents about keeping children down.