It is very very simple. Just as for IQ, the difficulty of a
mathematical question does not lend itself to objective
measurement. Therefore only feasible approach to assessing
performance of exam questions is (on the same lines as for IQ)
to grade according to the distribution of marks in a population
which has been exposed to the test.
When it comes to simply setting a Pass/Fail threshold, it
becomes sublimely simple. To achieve 50% (or 58%) Pass
rate, simply take the scores and draw a line such that just
50% (or 58%) are above it.
If, however, there is a mark (say 40/100) such that (say)
40% of candidates are above it and (say) 33% below it, so
that 27% have exactly 40/100, then randomly select a fraction
10/27 of these at random, and deem these to have passed.
The remainder are deemed to have failed. Then you have
50% Pass rate.
This method works even if all candidates score 0/100.
What could be easier? And with more respectable theoretical
foundation?
Michael Gove: Take courage. All is not lost!
Ted.
On 17-Jun-11 15:39:52, Paul Bivand wrote:
> He's probably going to norm-reference at school level and therefore
> ensure the target is met.
> ---------------------------------------------------------
> Paul Bivand
>
> -----Original Message-----
> From: email list for Radical Statistics
> [mailto:[log in to unmask]] On Behalf Of Kornbrot, Diana
> Sent: 17 June 2011 16:27
> To: [log in to unmask]
> Subject: Re: PASS
>
> Gove is planning for grade inflation to at least keep pace with
> monetary inflation, and hence deflation of teacher salaries Diana
>
>
> On 17/06/2011 16:22, "Tony Greenfield" <[log in to unmask]>
> wrote:
> What do you think of this
> From The Times 17 June2011
>
> Sir, How does Michael Gove expect secondary schools to have at
> least 50 per cent of their students reaching five or more
> A* to C grades including English and mathematics, when the
> Government currently force all the examination boards to have
> a pass rate of just 58 per cent in mathematics? As a teacher
> working in a non-selective school in a selective local authority,
> even with an Ofsted top award of outstanding by the Government's
> own inspectorate, this is an impossibility.
>
> Perhaps Mr Gove’s own mathematical skills are a little weak.
> Even if every school in the country had an intake of identical
> quality, he should know that for every school to achieve within
> 8 per cent above or below the national average pass rate is a
> statistical impossibility.
>
> Christopher Spark
> Head of Mathematics, Paignton Community and Sports College
--------------------------------------------------------------------
E-Mail: (Ted Harding) <[log in to unmask]>
Fax-to-email: +44 (0)870 094 0861
Date: 17-Jun-11 Time: 17:05:14
------------------------------ XFMail ------------------------------
******************************************************
Please note that if you press the 'Reply' button your
message will go only to the sender of this message.
If you want to reply to the whole list, use your mailer's
'Reply-to-All' button to send your message automatically
to [log in to unmask]
Disclaimer: The messages sent to this list are the views of the sender and cannot be assumed to be representative of the range of views held by subscribers to the Radical Statistics Group. To find out more about Radical Statistics and its aims and activities and read current and past issues of our newsletter you are invited to visit our web site www.radstats.org.uk.
*******************************************************
|