Sorry for not having underscored it in my previous post. I hope from Conroys' mail that it is now clear that Spearman/Brown split-half reliability is NOT Spearman's correlation and is NOT calculated by Stata's command -spearman-.
If Stata commands which I suggested in my reply to your first post are not satisfactory, you may think to use SPSS, or to calculate it by yourself (formula found in SPSS' help) as k*r/[1+(k-1)*r] where k is the number of items and r is the (Pearson's) correlation between the sums of the items in each of the two groups in which you splitted them.
Nicola
At 02.33 07/03/2007 -0500, you wrote:
>Date: Tue, 6 Mar 2007 17:27:17 +0000
>From: =?ISO-8859-1?Q?Ron=E1n_Conroy?= <[email protected]>
>Subject: Re: st: Reliability (Spearman/Brown)
>
>On 4 M�rta 2007, at 11:03, Vanessa Mahlberg wrote:
>
>>
>> I?ve got a (maybe very simple) question:
>>
>> I would like to calculate the split-half reliability (Spearman/
>> Brown) for a whole scala (including 14 items).
>
>The split half reliability is a very old method now. Essentially, it
>depends on the split. You can think of Cronbach's alpha as the
>average of all possible split half reliability coefficients.
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