[R] lme: subject-specific slopes.

John Sorkin jsorkin at grecc.umaryland.edu
Tue Dec 4 17:03:23 CET 2012


Ken,
Thank you for your help. ranef(fitRIRT) does not give me what I expect. The subject-specific slopes, and subject-specific intercepts are not anywhere close to what I would expect them to be; the mean of the subject-specfic values should be close to those reported by 
summary(fitRIRT) and they are not. As you will see by examining the material below, the subject-specific slopes are off by many order of magnitude. The intercepts are also far from the value reported in summary(fitRIRT). Do you have any thoughts?
Thanks,
John
 
> fitRIRT <- lme(echogen~time,random=~  1+time|subject,data=repeatdata,na.action=na.omit)> summary(fitRIRT)Linear mixed-effects model fit by REML
 Data: repeatdata 
      AIC      BIC    logLik
  495.097 507.2491 -241.5485

Random effects:
 Formula: ~1 + time | subject
 Structure: General positive-definite, Log-Cholesky parametrization
            StdDev       Corr  
(Intercept) 1.917511e+01 (Intr)
time        2.032276e-04 0     
Residual    1.044601e+01       

Fixed effects: echogen ~ time 
               Value Std.Error DF   t-value p-value
(Intercept) 64.54864  4.258235 32 15.158543  0.0000
time         0.35795  0.227080 32  1.576307  0.1248
 Correlation: 
     (Intr)
time -0.242

Standardized Within-Group Residuals:
        Min          Q1         Med          Q3         Max 
-1.61362755 -0.52710871  0.02948008  0.41793322  1.77340082 

Number of Observations: 58
Number of Groups: 25 > ranef(fitRIRT)   (Intercept)          time
1    -3.278112  2.221016e-09
2   -35.400618  4.314995e-08
3    11.493110 -6.797543e-09
4   -16.209586 -7.070834e-08
5     3.585227 -2.389705e-08
6     1.614320 -1.967700e-09
7     8.346905  5.827094e-08
8    30.917812 -3.768584e-08
9    -0.394101 -9.158251e-09
10    4.437509 -4.057971e-08
11   31.956597 -2.126275e-08
12   41.567402 -4.853942e-08
13  -10.723993  1.307152e-08
14   -4.554837  5.551908e-09
15   -4.554501  4.815086e-08
16   13.296985 -3.743967e-08
17   -8.255439  1.733238e-08
18  -21.317239  2.203885e-08
19  -13.480159  2.194016e-08
20  -13.044766  2.269168e-08
21   11.639198 -1.418706e-08
22  -27.457388 -1.154099e-08
23    2.194001 -5.509119e-09
24   -3.992646  7.682188e-08
25    1.614320 -1.967700e-09
 
 


 
 
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing)>>> Kenneth Frost <kfrost at wisc.edu> 12/4/2012 10:44 AM >>>
I think this might be close to what you want. ranef(fitRIRT)

On 12/04/12, John Sorkin  wrote:
> I am running a random intercept random slope regression:
> 
> fitRIRT <- lme(echogen~time,random=~ 1+time|subject,data=repeatdata,na.action=na.omit)
> summary(fitRIRT)
> 
> I would like to get the subject-specific slopes, i.e. the slope that the model computes for each subject. If I have 10-subjects I should have 10-slopes. I don't see the slope when I look at the items listed in 
> names(summary(fitRIRT)
> nor when I look at the items listed in 
> names(fitRIRT)
> 
> Thanks 
> John
> 
> 
> 
> 
> 
> 
> John David Sorkin M.D., Ph.D.
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
> Confidentiality Statement:
> This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. 
> 
> 
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--
Kenneth Frost
Graduate Research Assistant - Dept. of Plant Pathology
University of Wisconsin - Madison
Lab: (608) 262-9914
Mobile: (608) 556-9637
kfrost at wisc.edu


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