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Secondary education

Connect with other parents whose children are starting secondary school on this forum.

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Original poster

School League tables - CVA

20 replies

magentadreamer · 28/10/2011 11:51

I've often read on here comments like " a CVA of 1030 is good that means that DC are getting 3 grades above what they should at GCSE" *I've plucked those figures out of thin air.

How do you come to that fact? I was looking at a the 2010 league tables and wondered how short DD's school and another school were selling their students. DD's school has a 53% 5 A*-C including M&E the other school a 71%. The CVA are 989 and 983. I noticed alot of local schools have CVA around this level.

OP posts:

IndigoBell · 28/10/2011 12:04

If every child got what they 'should' get CVA would be 1000.

So CVAs below 1000 aren't good. But then neither is it a very good measure....

In fact the govt is scrapping CVA and going back to VA this year, so even they have decided they got it a bit wrong.....

Also you need to look over several years, not just one.

Having said that, I do look at CVA. I had a choice between 2 schools. One that got higher % passes, but lower CVA. And I went with the other one that had lower % passes and higher CVA . OFSTED was very critical of the school with high passes but low CVA and said that the school did not get the results it should.......

Original poster

magentadreamer · 28/10/2011 12:10

Thanks, I did realise that they were a bit of a wooly measure - but then aren't all league table measures. I was intrigued as to how those in the know could look at a CVA and say that school gets 3 grades more at GCSE or less.

OP posts:

IndigoBell · 28/10/2011 12:13

Oh, because they work at schools and understand how it's calculated.

But the formula's really complicated, and nobody really understands it :)

Original poster

magentadreamer · 28/10/2011 12:18

And heres me thinking it would be something simple.....

OP posts:

prh47bridge · 28/10/2011 12:28

CVA is supposed to measure pupils' progress compared to other children from similar backgrounds. However, there are real questions as to whether it is statistically valid so it is being phased out.

IndigoBell · 28/10/2011 12:41

I'm fairly sure nobody understands it:

community.tes.co.uk/forums/p/522668/7034067.aspx#7034067

yotty · 28/10/2011 14:07

What does CVA stand for? I thought it was a cerebrovascular accident, ie. A stroke!!

academyblues · 28/10/2011 14:13

Contextual value added. Taking into account existing statistical differences in progress between different social groups and taking this into account when analysing data demonstrating progress between KS1 and KS2.

As prh says, the 'contextual' is going to be taken out of the value added analysis.

IndigoBell · 28/10/2011 14:14

Context Value added

as opposed to Value Added

which means it also takes into account things like the gender and ethnicity of the students before predicting what grades they should get.

So value add is whether they made the predicted progress based on their KS2 results, and CVA is whether they made the predicted progress based on their KS2 results and their gender / ethnicity / postcode.....

I'm not clear what the difference between Value Added and % students making 2 levels of progress is.....

sheeplikessleep · 28/10/2011 14:19

I don't think they are actually statistically significant, if I understand this very old report correctly ...

news.bbc.co.uk/1/hi/education/3401219.stm

academyblues · 28/10/2011 14:23

I expect you're right that no-one understands these measures, indigo.

Especially Gove et al who know next to nothing about state education yet seem very determined to sell off our schools on the basis of them.

[hhmm]

prh47bridge · 28/10/2011 15:39

Schools are not being sold off.

academyblues · 28/10/2011 15:46

Really? Taken out of LA control with a private sponsor put in charge?

prh47bridge · 28/10/2011 17:51

As I have pointed out to you previously most of the new academies do not have sponsors. Even where there are external sponsors the school is not in any way sold off. The land and buildings remain the property of the LA.

academyblues · 28/10/2011 18:11

That is a matter of ideological and political perspective, rather than fact, I would say.

noblegiraffe · 28/10/2011 18:22

I was intrigued as to how those in the know could look at a CVA and say that school gets 3 grades more at GCSE or less.

Because of how the CVA is calculated, 6 points = 1 GCSE grade increment. So a CVA of 1006 means that on average, each student in the school got 1 grade higher in 1 GCSE subject out of their 8 best GCSEs compared to similar students from a similar school. 994 means they got on average 1 grade lower in 1 GCSE. 1048 means they got on average 1 grade higher in each of their 8 best GCSEs than a similar cohort in a similar school.

I'm not clear what the difference between Value Added and % students making 2 levels of progress is.....
2 levels of progress is a static measure. CVA is a 'real time' calculation. It looks at how students did that year and compares them against each other. So if boys as a group do badly one year, then if the boys in your school do badly, but in line with the national average, your CVA isn't affected. If boys in your school do badly in a year that boys do well then your CVA goes down.
I'm not sure about the new value added measure, but expect it will be a similar comparison of their results against students who got the same KS2 results, but ignoring the external factors which affect progress which are currently taken into consideration in the CVA score.

IndigoBell · 28/10/2011 19:30

noble - thanks! That's the first time I've understood VA.

admission · 28/10/2011 19:37

Ah, but it is not as simple as that because you also have to factor in the accuracy of the figures, because it all about averages. The smaller the school the less accurate the predictions and therefore the bigger the variance. So whilst the CVA might be 1000, the variance could easily be 994 to 1006 or wider. In this example the two extremes represent not doing quite as well as expected to doing slightly better than expected. The more pupils that are taking the exam in the school the greater the accuracy and the less the variance will be.

prh47bridge · 28/10/2011 20:11

academyblues - Most of the new academies do not have sponsors. The land and buildings remain the property of the LA and are not sold to the academy even when there is a sponsor. Those are facts. They are not matters of ideological and political perspective.

academyblues · 28/10/2011 20:53

admission makes a very good (and not pointed out enough) point about some of the problems in using percentages with small numbers. This is obviously more significant in primary schools because they're smaller, and especially single form entry.

In a 2 form entry school, 6 pupils are 10% of the whole; in a single form entry, just 3 pupils equate to 10%, possibly even more if it's undersubscribed. 10% difference in KS scores between schools/years in schools looks hugely significant, but it's clearly not if it involves 2 able pupils just missing a L4 and 1 moving house and school at Easter.

This affects the CVA/VA but I don't understand the formula enough to explain exactly how much by.

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