Hello redsky:
I thought I'd write about what advantage achieving Level 6 has had for DD1 now in Y7 at a school that only teaches mathematics in mixed ability during the entirety of KS3.
Achieving Level 6 means that her end of targets/ end of Key Stage targets are very high indeed (currently end of Year target is 7c and end of Key Stage 3 target in NC L8*+ territory - my understanding is the school levels don't go beyond this but in school testing at end KS3 (there is no national SATs test end KS3 now) will spot achievment beyond Level 8).
DD1's school did not in any serious or concerted way teach content for the NC L6 test. There view throughout all but Year 6 was that they were "only required to teach to NC L4" and NC L5 was a "very high level of achievement".
Remember that the senior school's VA score is linked to your child's KS2 SATs achievement (that's the official figure the secondary school HAS TO work from). So the benchmark Nc L4 at end Ks2 goes on to NC L5/6 end of KS3 (1 - 2 NC levels improvement on KS2 results).
I can't find any definitive governmental statement on equating Nc levels to GCSE results - but this discussion of TES (community.tes.co.uk/tes_assessment/f/82/t/344140.aspx) seems to have the following consensus: NC L7= C at GCSE; NC L8=B at GCSE, NC L9=A at GCSE, NC L10=A at GCSE. Now of course the GCSE scoring system is changing to a 1 - 9 system whereby a 9 is the top 2/3rds performance at A on present GCSE scheme: source: www.theguardian.com/education/2013/jun/04/gcses-i-levels-ebacc-ofqual-exams
I think for mathematics the first thing to absorb for your child is that NC Level 5 isn't a huge achievement. about 40% of pupils in England are doing that year on year: source: www.theguardian.com/news/datablog/2013/sep/19/sats-results-key-stage-two - scroll down to SATs KS2 Maths data table at bottom.
That has them finishing Year 9 on a target of NC L6/7 for the school (remembering that Nc L7 equates roughly to a C grade at GCSE two year's later at end Year 11). So for your son to just work to target he'd have to improve two full NC Levels to achieve an A at GCSE (in old money) - and my understanding is that the requirments for the new maths GCSE (which he will sit 5 years from now) will be even tougher.
So when you ask is it worth him going for it - yes - because as you say you have a son who needs pushing (and I presume you don't always want to be the one pushing?) - so achieving NC L6 will push his secondary school to get him to Nc L7/8 by end Year 9 and NC L9/10 by end Year 11 (i.e. A/ A* territory).
Now that may not be important to you for any number of reasons - but my understanding is in terms of STEM subjects (so if he wants to be a VET/ go into medicine/ do a hard science/ study engineering etc....) it will give him many more university options than a B at A Level.
My view is this. There is no cost to sitting a Level 6. It's like going for a slightly higher bar in the high jump. You've made Level 5, why not have a go at Level 6 - you have the chance and you won't find out unless you try. Yes I agree odds are your son will only just scrape into NC L6 territory (after all that's the high end of average ability of end KS3 students) - but what an achievement if he does eh? I suppose the way to think of this was if this was an athletics opportunity - a chance to swim or run faster than before/ score more goals or the winning goal/ etc.... would you or your son baulk at the opportunity?
HTH
PS by the way there are a number of things your son can do at home which will help prepare him for NC L6 maths testing (even if only over Easter break).
He could for instance learn about algebra (which seems to be the real separator): things like Khan Academy (free) or Maths Factor (subscription) are a real help there.
Make sure he really knows how to handle and interchange between ratio/ proportion/ percentages. Woodlands Junior School Maths Zone (free) can help there. Also Mathsfactor (subscription).
Make sure he gets fractions (how to add/ subtract and multiply)/ how to reduce to lowest common demoninator or find common denominators (classic question is to be given 3 fractions and work out which is the smallest or largest).
Make sure long division/ multiplication - so something along the lines of 4365 divided by 13 or 435 x 87 are secure.
Consider investing in a KS2 SATs L6 workbook - select one that also teaches these calculation skills.
It is a short time until May 11th - just 2 months. But some real breakthroughs can occur in those months.
15 minutes a day x 60 days = 15 hours of maths learning = 3 weeks of school (well more actually as the pace/ standard will be higher) & bearing in mind he'll be doing L6 work in school as well - a whole heap of skills can be picked up or reinforced in these next few weeks. After all 12 points (the difference between his 20 and the 32 required to pass) probably equates to