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PostPosted: Wed Oct 24, 2012 9:32 am 
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Joined: Sat Oct 20, 2012 8:52 am
Posts: 8
Hi Fedup, we only wanted Upton too so didn't sit the Wirral exam and kicking ourselves now. I have emailed the Upton HT and I'm waiting for a response so will let you know how I get on.

I was hoping to hear back before the deadline for the preference forms, but it seems unlikely. So the plan is to put Upton first and await the appeal in March. I think that the raw score will be useful at the appeal as most reasonable people would accept that a score of 64/75 demonstrates ability. It might be worthwhile you asking them for your daughters raw scores too.


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PostPosted: Wed Oct 24, 2012 3:06 pm 
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Been on to GL assessments to query the standardised scores lower on one paper compared to other - they said they could not comment on an individual case and we had to speak to the school involved. Feel like banging head against a brick wall!


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PostPosted: Wed Oct 24, 2012 3:57 pm 
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Nove I have PM'd you


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PostPosted: Thu Oct 25, 2012 2:57 pm 
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Joined: Mon Aug 31, 2009 6:19 pm
Posts: 532
Location: bucks
Hi all

Nove pm'd me as i have looked at some standardisation issues in bucks before and i think you have the same issue we have, i have never been involved in exam standardisation before but i have alot of experience with stats.

to explain what i think is the issue and just in case you are not familiar with standardisation the exam board web sites explain that basically standardisation follows this formulae:

Standardised Score = 15x(RawScore — meanscore)/sd + 100

so in essence all the results for the paper are analysed and a mean and standard deviation (a measure of the spread of results ) are calculated. For each childs results the difference between their score and the mean score is calculated so if the mean score is 55/75 and your child got 65 then the difference is 65-55 =10, you then divide this by the standard deviation to get their score as a number of standard deviations from the mean. So if the standard deviation is 15 raw score points then they are 10/15 or 0.66 standard deviations above the mean. This is then mulitplied by 15 (not sure why 15 is chosen) so that if their score is 1 standard deviation above the mean then this would give 15 or in our case 0.66 x 15 = 10. This is then added to 100 to give the standardised score. So a child who gets 1 standard deviation above the mean score gets 100+15 = 115 ss and 2sd above would get 130 etc.

However this is all the information we get from the exam boards, and we look at actual raw score and ss results then the above analysis is clearly not what is happening. The above formula would give a constant value for SD across all scores which is not what we see in practice at all, in bucks we have had lots of raw score vs ss data which is in this post:

viewtopic.php?f=12&t=18356

Which demonstrates this.

Also if we look at Nove's dc's results 64/75 RS = 111 ss and 69/75 RS = 116 ss this would imply that the standard deviation for this paper is 5 x3 =15 rs ( (as 64 to 69 (5rs) gives 111-116 ss (5ss) so 1 sd (15ss) = 5x3 rs) ). However this can't be the case as for scores above 69 to 75 ie 6 rs produces 24 ss or 24/15 or 1.6 SD's making 1 SD = 3.75 rs.

So for paper 1 the standard deviation of the scores (or value of each standardised mark) reduces as the score increases.

The reason for this can only be speculated as the exam boards seem to keep the analysis that they do very secret. My explanation for this non linearity is that basically the paper is too easy or the children who take the paper are doing alot better than the children who tested the paper. So if you looked at the results of the paper i suspect you will find that the results are bunched to the upper end of the scores and then have a steep drop in the distribution curve from around 68-75 ie the distribution of results is not a lovely binomial but a nasty -ve skewed distribution (see second diagram down on this link http://mvpprograms.com/help/mvpstats/di ... ssKurtosis )

This means that each extra mark a child gets is hugely more significant as the score increases (or the ruler stretches out see this post :

viewtopic.php?f=12&t=18108)

This gives v poor resolution for the exam and is thus a v. coarse assessment.

So i think the problem with paper 1 was that it was actually too easy and so loads of children got too high scores and the pass mark was decided on by too few v difficult questions.

I'm not sure this helps for appeal or not i am by no means an expert on this.

Hope this makes sense let me know if there is anything you are not sure about .

Tree


Last edited by Tree on Thu Oct 25, 2012 6:22 pm, edited 1 time in total.

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PostPosted: Thu Oct 25, 2012 5:04 pm 
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Joined: Thu Oct 18, 2012 6:23 pm
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wow! thats gone right over my head, but full marks for such a detailed explanation :D .


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PostPosted: Thu Oct 25, 2012 5:23 pm 
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Thanks Tree - love the Tall School story :lol:

Very complex but I think I get the gist of it; between the raw scores of 70 and 75 there would be big jumps in the SAS making each additional raw score mark worth proportionally more standardised score marks.

It isn't common sense; and doesn't seem fair. Also, I'm not sure how the age standardisation affected? It could definitely explain our results, however we would still expect a fair proportion to pass. I still haven't heard of anyone on the forum, or from school who passed Paper 1, never mind score 130+.


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PostPosted: Thu Oct 25, 2012 5:49 pm 
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Joined: Tue Jun 26, 2012 12:02 pm
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Tree i am completely :shock: :? glad i am glad my dd passed as i think it would take me ages to figure it all out

Nove and fedup2012
not sure if your dds are practicing catholics but if they are would this also help in your appeals with it being a Catholic school


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PostPosted: Thu Oct 25, 2012 7:28 pm 
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Joined: Thu Mar 01, 2012 9:55 am
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Wow tree, that was some explanation! I will have to sit and study it to really understand the process.

As Nove said I have still not found anyone who passed paper one. If anyone feels they could share there results with us, it may give us a better idea of, if there was a problem with the marking formula or not.

I am really shocked at how high the raw score would have to be on paper 1 to actually pass it. I just wish we had more access to facts and figures so that we could have a better understanding what is going on.

The other thing that I find strange is that one paper was out of 75 and the other out of 85? is this the same every year?


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PostPosted: Fri Oct 26, 2012 6:37 pm 
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hi all you requested test results for upton my ds score was paper1 128 p2 139 and passed both papers but still lower on paper 1 hope this helps


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PostPosted: Sat Oct 27, 2012 8:15 am 
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Thank you Test46
The thing that concerns me is this: My son took 11+ the other year he scored 129 first paper and 132 second paper, his friends scored 127 & 124, 140 & 140, 115 & 119 etc

The point being they all scored similar scores on first and second papers (I know you can have exceptions ie running out of time, nerves etc) but generally you could see where they fitted on the ladder.

Test46 your daughter is obviously a very bright girl and scored nearly 100% on that 2nd paper. My point of view would be she would be bright enough to score similar on the first paper?

But if you look at the scores from the forum so far:
111 & 120
109 & 122
114 & 137
128 & 138

If you appled an extra 10 marks to all of the first scores they would then be of a similar standard. ie: 121 & 120, 119 & 122, 124 & 137, 138 & 138

Has the figures for the test been calculated as two tests of 85? instead of 1st test one out of 75 and 2nd test 85?

I could be completely wrong and probably am, I just can't help thinking how can you decide which score best reflects your childs ability when they are so far apart on all examples? I know this is only a very small snap shot, but I would always wonder if I did'nt share my points of view with you all.


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