"John W. Kulig" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > JP wrote: > > > I have been unable to find an adequate explanation of exactly what is the > > difference between an interclass and in intraclass correlation, and the > > circumstances in which you would choose either. > > Ian Kestin > > This is in answer to the second half of your question: Use the interclass > when you are correlating two different things, such as height and weight. You > can go through the entire data set of paired scores and it is obvious which > number in each pair is a height (call it A) and which is a weight (B). > Intraclass correlations are used when there you cannot do this. They are used > (as one example) to get correlations for twins. If you had a set of IQ scores > from twins, each pair of IQ scores is from a twin pair - but there is no > basis for assigning one A and the other B. Each member of a twin duo could as > easily be thrown into column A as column B. > > Thankyou, this does help, although the data I have does not fit either of your examples. I have a single candidates answer sheet to 12 questions (each question is scored 1, 2, 3, or 4) which has been marked by 15 different examiners. I wish to have a single number to assess overall inter-examiner agreement. I had thought that interclass correlation wass the correct technique, but was told I should be using intraclass correlation instead, and have been unable to find a convincing explanation ever since. Ian Kestin > ------------------------------------------------------------------ > John W. Kulig [EMAIL PROTECTED] > Department of Psychology http://oz.plymouth.edu/~kulig > Plymouth State College tel: (603) 535-2468 > Plymouth NH USA 03264 fax: (603) 535-2412 > ------------------------------------------------------------------ > "Kane to kal� ke r�chto sto yal�." > (Do a good deed and cast it to the sea) > Ancient Greek saying > ------------------------------------------------------------------ > > > . > . > ================================================================= > Instructions for joining and leaving this list, remarks about the > problem of INAPPROPRIATE MESSAGES, and archives are available at: > . http://jse.stat.ncsu.edu/ . > =================================================================
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