[R] how to get "lsmeans"?

[Frank E Harrell Jr]

John Fox wrote:
> Dear Frank,
> 
> The object is to focus on a high-order term of the model, holding other
> terms "constant" at typical values; in the case of a factor, a "typical
> value" is ambiguous, so an average is taken over the levels of the factor.
> If the factor is, e.g., gender, one could produce an estimate of the average
> fitted value for a population composed equally of men and women, or of a
> population composed of men and women in proportion to their distribution in
> the data. Otherwise, one would have to produce separate sets of fitted
> values for men and women, with the number of such sets increasing as the
> number of levels of the factors held constant increase. On the scale of the
> linear predictor, these sets would differ only by constants.
> 
> Regards,
>  John

Makes sense.  I just set other factors to the mode, and if it is 
important to see estimates for other categories, I give estimates for 
each factor level.  If I want to uncondition on a variable (not often) I 
take the proper weighted average of predicted values.

Cheers
Frank

> 
> --------------------------------
> John Fox
> Department of Sociology
> McMaster University
> Hamilton, Ontario
> Canada L8S 4M4
> 905-525-9140x23604
> http://socserv.mcmaster.ca/jfox 
> -------------------------------- 
> 
>> -----Original Message-----
>> From: Frank E Harrell Jr [mailto:f.harrell at vanderbilt.edu] 
>> Sent: Thursday, March 22, 2007 8:41 AM
>> To: John Fox
>> Cc: 'Prof Brian Ripley'; 'r-help'; 'Chuck Cleland'; 'Liaw, Andy'
>> Subject: Re: [R] how to get "lsmeans"?
>>
>> John Fox wrote:
>>> Dear Brian et al.,
>>>
>>> My apologies for chiming in late: It's been a busy day.
>>>
>>> First some general comments on "least-squares means" and 
>> "effect displays."
>> ... much good stuff deleted ...
>>
>> John - the one thing I didn't get from your post is a 
>> motivation to do all that as opposed to easy-to-explain 
>> predicted values.  I would appreciate your thoughts.
>>
>> Thanks
>> Frank
>>
>> -- 
>> Frank E Harrell Jr   Professor and Chair           School of Medicine
>>                       Department of Biostatistics   
>> Vanderbilt University
> 
> 


-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University