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September 2, 2017

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Grade (un)reliability - the full story

June 21, 2019


Over the last few weeks, I've been working on a document that tells the full story about grade (un)reliability, including


*  why grade reliability matters

*  the problematic nature of the quest for the 'right' mark

*  the distinction between 'accuracy' and 'reliability'...

*  ... and how grades can be unreliable even when marking is technically perfect

*  the 'lottery-of-the-first-mark'

*  the inherent 'fuzziness' of all marking

*  how to measure fuzziness

*  the evidence about how (un)reliable grades actually are

*  some simulations of 2018 A level Biology and 2018 GCSE English Language

*  a description of 21 possible ways to deliver reliable grades (some of which work better than others...)

*  ...and an analysis of why double-marking doesn't work at all

*  some implications of the various possibilities

*  a full analysis of the statistics of marking and re-marking.


Much of the content has appeared elsewhere, in bits; this document brings (I think) all the main things together into a single place. 


The document is long (!!!), but I trust well-structured; please do be in contact of you have any thoughts, questions or suggestions, and especially if you disagree with anything  - and indeed if you find any mistakes (which are my fault, and for which I apologise in advance!).


To read or download the document, please click here.







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