[R-sig-ME] clogit error message

[Federico Calboli]

On 31 Mar 2010, at 15:02, NJ Robinson wrote:

> The sample size of my data is 30 (comprising 15 pairs grouped by "site").
> My sample data is composed of a binary response ("response") and 3
> predictor variables all of which are factors ("x1","x2","x3").
> 
> The following command was used to construct the model;
> 
>> clogit(response~x1+x2+x3+strata(site))
> 
> based on the example of my data structure seen below,
> 
> Have i used the correct syntax in order to run the model correctly for my
> data structure?
> 

can you check with str(data) that x1, x2, x3 and site are factors? By eye I'd say your syntax is correct.

Best,

Federico

--
Federico C. F. Calboli
Department of Epidemiology and Biostatistics
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG

Tel +44 (0)20 75941602   Fax +44 (0)20 75943193

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