CEM tears and fears

[paperino]

Well it depends in on the proportion of summer/autumn children taking the exam. There is probably a self selection there, older children generally perform better at school, so parents of summer children, possibly ignoring the age standardisation, do not enrol their children for the 11plus.

[Tramps13]

Paperino, I am sure you are right, although we don't have figures showing enrolment ages by month of birth.

As you say, older children generally perform better at school, and it is this issue that should be addressed.

[mystery]

From the admissions figures, over the last three years at the three South Warwickshire Grammars the entries in total are:
186 children born Jun/Jul/August
236 children born Sept/Oct/Nov
I think that this will make any appeal based on unfair bias against older children quite difficult.

Why?

[Tramps13]

I'm sorry mystery, I probably haven't explained myself very well.

A lot more older children go to South Warks Grammar schools than younger children (over 25% more in the last three years). Therefore in my opinion, it would be difficult to argue that older children are being discriminated against in the admissions procedure.

[mystery]

I'm sorry mystery, I probably haven't explained myself very well.

A lot more older children go to South Warks Grammar schools than younger children (over 25% more in the last three years). Therefore in my opinion, it would be difficult to argue that older children are being discriminated against in the admissions procedure.

Ah sorry I misread you. I read older as younger. It looks like younger children migh be bein discriminated against.

[Airina]

No you can't work it out from the standardised scores. But we do know it's nothing like 88%. Last year (2012 exam for 2013 entry) the average raw marks were:

VR = 56 out of 111 (somewhere between 50 and 50.9% allowing for rounding)
Num = 10 out of 42 (between 22.62 and 25%)
NVR = 18 out of 32 (between 54.69 and 57.81%)

What puzzles me that in my DC’s result letter it has said that in numeracy for example out of available 181 points my DC scored 104. It does not seem to match 10 out of 42 for numeracy quoted above.
And when I asked how many questions approximately my DC managed to get done - the reply was perhaps two thirds. That answer matches the numbers in the results letter.
So how 10 out of 42 could get transformed into 104 out of 181 available?

[Okanagan]

No you can't work it out from the standardised scores. But we do know it's nothing like 88%. Last year (2012 exam for 2013 entry) the average raw marks were:

VR = 56 out of 111 (somewhere between 50 and 50.9% allowing for rounding)
Num = 10 out of 42 (between 22.62 and 25%)
NVR = 18 out of 32 (between 54.69 and 57.81%)

What puzzles me that in my DC’s result letter it has said that in numeracy for example out of available 181 points my DC scored 104. It does not seem to match 10 out of 42 for numeracy quoted above.
And when I asked how many questions approximately my DC managed to get done - the reply was perhaps two thirds. That answer matches the numbers in the results letter.
So how 10 out of 42 could get transformed into 104 out of 181 available?

It isn't 104 out of 181.

Standardised scores are quoted relative to the average (100), and determined by how many standard deviations away from the average the score is.

Standard score is 100 + ((actual score - average score)/standard deviation in scores)x15)

A total maximum of 181 implies that 42 was 5.4 standard deviations above the average - i.e that the standard deviation of the scores was between about 5.8 and 6.2 depending upon the actual average (10 being rounded to the nearest integer presumably). Your 104 for an score of 10 could mean that the average was actually slightly below 10, and/or that age adjustment (which typically means younger children end up with a slightly higher standardised score for the same mark) had pushed the score for a younger child to slightly over 100 - probably both.

e.g. If the actual average was 9.6, the standard deviation to produce a maximum of 181 would be 6. A score of 10 would be 0.06666 (i.e. 0.4/6) standard deviations above this, producing a score of 101. Then if your child was younger in the age group there might well be an adjustment for this.
Each extra raw mark would have meant about 2.5 extra marks on the standardised score.

[mystery]

Okanagan, the average raw marks that you quote- which sort of average are those? Are these typical of c e m tests in all areas? It is incredibly low for the maths. Are children aware how few they are completing / getting right?

[Okanagan]

That was last year - and everyone was surprised when we found out how low it was. The figures we've seen so far for this year suggest that the numeracy probably wasn't as hard (full marks would have meant 154 - or 3.6 standard deviations above average, compared to last year 181 - or 5.4 standard deviations above average).

[Airina]

Thank you, Okanagan, for the explanations. It is getting a bit clearer now.
10 out 42 is just so low, I am really surprised by those numbers. How disheartening it must have been for the children.
My DC is a summer one.