[Rasch] split half reliability

Parisa Daftari Fard pdaftaryfard at yahoo.com
Fri May 22 18:43:57 AEST 2015

Thank you Gregor for you nice attention,

By NRT I mean norm reference test where data form  normal distribution, whereas CRT means criterion reference test where data may form skewed distribution.

like Pretest and Posttest we have less variation in CRT 

So you think Split half is better with pretest and posttest in experimental design?

On Fri, 5/22/15, Gregor Sočan <gregor.socan at ff.uni-lj.si> wrote:

 Subject: Re: [Rasch] split half reliability
 To: rasch at acer.edu.au
 Date: Friday, May 22, 2015, 12:37 PM
 I do not agree with Tom. It is
 certainly not a bogus measure, except if 
 you consider the classical test theory to be a
 bogus measurement 
 paradigm. ;-) 
 Split-half reliability basically provides the same kind 
 of information as alpha, that is, a lower bound
 to the sample 
 reliability. Of course, both
 of them make sense only in the classical 
 test theory framework.
 Split-half gives more accurate results than alpha when the
 items are relatively heterogeneous and
 you can divide them into two 
 groups: so, I guess that in your case split-half might
 really be 
 more approapriate than alpha
 (although I do not know what exactly is 
 meant by NRT and CRT - are these measurements
 comparable to conventional 
 test items?).
 The original reference is Guttman's (1945)
 paper in Psychometrika.
 Best regards, Gregor
 Dne 22.5.2015 ob 8:27 je Tom Conner
 > Parisa,  I don't know
 the answer to your specific question.  But I do
 > know that split half reliability is a
 bogus measure.  It tells you
 > nothing
 that is not contained in the variance.  I recommend you not
 > it unless a journal requires it.
 > tlc
 > On 5/22/15 4:39 AM,
 Parisa Daftari Fard wrote:
 >> Dear
 >> I
 apologize to interrupt the ongoing discussion. I have been
 reading articles on dynamic assessment. One facial
 difference between such papers and others is that they
 reported split half reliability instead of Alpha. Is this
 due to the fact that DA is half NRT and Half CRT? I
 appreciate it if you help me with your incisive suggestion
 and readings.
 >> Cordially
 >> Parisa
 >> Parisa
 >> IAU (South Tehran
 >> Rasch mailing list
 >> email: Rasch at acer.edu.au
 >> web: https://mailinglist.acer.edu.au/mailman/options/rasch/connert%40msu.edu
 Rasch mailing list
 email: Rasch at acer.edu.au
 web: https://mailinglist.acer.edu.au/mailman/options/rasch/pdaftaryfard%40yahoo.com

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