Standardised scores - Kent

[Mamonaku]

A quick Google search tells me that Mensa use the Cattell 3B and Cattell culture fair 3 tests.

Unlike most other normal distribution curves relating to intelligence (11plus, CAT score, most other IQ tests) these tests have a standard deviation of 24 so a score of 142 on either of these Cattell tests would not be comparable to the GL normal distribution curve (it's online, complete with percentiles, standard scores and stanines).

Looking at GL's normal curve of distribution right now I can clearly see that they would class a standardised score of 130 as being in approximately the top 2%

The point is that a standardised score of 130 for a GL supervised test usually equates to the top 2% of an entire population, and the top 2% of an entire population would get into Mensa.

A score of 142 on a Cattell test with a standard deviation of 24 is not comparable to a score of 141 on a GL supervised test (maximum score for Kent Test) with a standard deviation of 15.

The information is all online.

[Tea For Two]

Well, if others are to be believed then the total number who scored 423 and over for 2012 is 660 with 880(approx) getting 420 and over.

So is there a huge wedge of tutored DC skewing the results?

[anotherworriedmum]

Well, if others are to be believed then the total number who scored 423 and over for 2012 is 660 with 880(approx) getting 420 and over.

So is there a huge wedge of tutored DC skewing the results?

So do the SSs in Kent have 880 spaces between them? If so the rest of us with high scores that would have got in in years gone by are not going to get anywhere near them.

[mystery]

We'll never know if a huge wedge of "tutored" pupils skew the results, just the same way we won't know if a number of primary schools getting able children to level 5 in maths earlier than average might also skew the results.

Are the numbers getting these high scores any different from past years? Don't forget there are children who have taken 11plus tests in more than one county and passed them, so not all these children will be looking for a Kent Superselective place, and some will go independent too. Unless the numbers are vastly different from in previous years there shouldn't be any more of a problem than usual with admissions.

It just shows though that they're splitting hairs with the SS cut-offs. The tests are not really designed to discriminate this finely - it's just a convenient way of sorting children by test score. When you start to think about confidence intervals etc it's all very approximate despite the apparent scientific neatness of the cut-off method.

[DaddyOh]

I've spoken to KCC and they tell me that the standard deviation has not changed but the treatment of the fat tails of the Kent distribution has changed. Sounds like an odd thing to do in my opinion but hey, who am I to argue.

Putting aside the statistical treatment for a moment (since kent always had fat tails it's not actually that helpful to talk about normal distributions anyway since the treatment doesn't include higher moments) the really important bit of information is that KCC tell me there are more 423's this year than there were 420's last year. That probably means we can expect the cutoffs for the SS's to be higher this year than last year. Of course that all depends on where the high scores were and where they apply for so only allocation day will tell us for certain.

Hope that helps and good luck to everyone for the 1st of March.

[DebP]

How did you get a score from British Mensa? Traditionally they never gave a score because the whole point of being in Mensa is that you are in the top 2% of the population. There is no pass or fail score to get in order to "scrape in".

If Kent results don't fit a bell curve then I would be very surprised since they are administered by GL assessment who standardise against a normal distribution curve (as previously stated). Standardising requires a mean and standard deviations from the mean - hence a normal distribution curve.

When I spoke about a score to scrape in I didn't mean it as literally as you seem to take it.
Many years ago I had an IQ test administered my mensa.
My IQ was assessed as 142 and an IQ of 142 was the lowest possible for Mensa Membership.

Any way, you have obviously found out a lot more about the Kent Test than I had even thought about. It is very interesting and makes those mid range passes so much more impressive.
So A score of 360 puts children in top 21% and a score of 390 puts them in top 2 % (approx).
Some are mentioning actual numbers of kids who pass at 420-423.

Does anyone know, are there official figures published anywhere so we can confirm how many passed at 390+, 380+, 370+?

[doodles]

So do the SSs in Kent have 880 spaces between them? If so the rest of us with high scores that would have got in in years gone by are not going to get anywhere near them.

AWM, I know there will be some people disappointed on 1st March (there always is) but remember that quite a large number of these children will have sat several tests (Kent, Bexley, Medway, St O's etc) and as clever as they are they won't take 3 places each Hopefully this will reduce the number of actual places required.

[pheasantchick]

Tea for Two :

Judd has 125 places - boys

Not sure about other schools

[yoyo123]

not all the children who were high scorers will want to go to the superselectives.

we have clever children over here in the far east too!

[doodles]

Exactly yoyo, they are spread all over the county, are girls and boys and some will have done more than one test or be off to an indie instead.