Hi:
Schools should be using APP (in England at least) - which stands for Assessing Pupils Progress. Information & the guidance document can be found here at DfE website: www.education.gov.uk/publications/standard/_arc_SOP/Page6/DCSF-00129-2009
The document does state: Curricular targets, informed by APP, can be shared with pupils and parents to support discussions about where pupils are in their learning and what they need to do to progress.
Now although this is optional. Schools are funded by government (therefore the tax payer). This means that they are subject to Freedom of Information legislation. Nobody has had to test this - but you are well within your right to ask to see any lesson plans, e-mails, etc... related to your child, as their legal guardian. Therefore, since the school will most likely be gathering this data you are entitled to see it.
I suspect that if you ask, the school will realise that you're only asking for them to communicate the data they've already gathered - you're not really creating a lot of work.
Our school was very resistant at first, but since deciding to roll out feedback about APP results to parents at parent/ teacher meetings and to children it has helped everyobdy be more focused about what is required to move from a 3a to 4c (on SAT levels) in maths, for example.
I'm not certain that it has radically improved my understanding of how my child is doing - but it is 100% more information than I was getting before and seems much more pertinent than 'DD1 enjoys all forms of movement and is paritcularly fond of dancing'. And other 'lovely to teach' type statements that tell you nothng in terms of reading, writing and arithmetic.
An example of the information you can gain is here for APP reading scales:
portfolio.pebblepad.co.uk/cumbria/viewasset.aspx?oid=301842&type=webfolio&pageoid=315049
Examples of APP maths grids here from North Somerset Council: www.n-somerset.gov.uk/Education/Learning/thelearningteam/appgrids.htm