st: Line of equality in scatter plot

["LL Miller, Avon Longitudinal Study Parents and Children" <L.L.Miller@bristol.ac.uk>]

Afternoon all,

I'm trying to assess the reliability of a continuous variable with the same 
variable assessed by a second person. I have used alpha var1 var2 to get 
Cronbachs alpha but wanted to see what it is doing visually. I created a 
scatter plot but can't find any option that will allow me to draw a line on 
the plot through the diagonal i.e. where the points should fall if there is 
no difference in the two assessments.

I have encountered several other useful things like ovfplot for after 
regression plots but this since I am not doing regression this is not quite 
what I want.

Does anyone know how to do this?

Cheers

Laura

----------------------
Please note new address and contact details from 22nd July 2008
LL Miller, Avon Longitudinal Study Parents and Children (ALSPAC)
Department of Social Medicine
University of Bristol
Oakfield House
Oakfield Grove
Clifton
Bristol BS8 2BN

Room number: BS9
Phone: +44(0) 117 331 0105
Fax: +44(0) 117 331 0080
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