R: Five Published Trails from Berkey et al. (1998)
Berkey98
R Documentation
Five Published Trails from Berkey et al. (1998)
Description
The data set includes five published trials, reported by Berkey et al. (1998), comparing surgical and non-surgical treatments
for medium-severity periodontal disease, one year after treatment.
Usage
data(Berkey98)
Details
The variables are:
trial
Trial number
pub_year
Publication year
no_of_patients
Number of patients
PD
Patient improvements (mm) in probing depth
AL
Patient improvements (mm) in attachment level
var_PD
Sampling variance of PD
cov_PD_AL
Sampling covariance between PD and AD
var_AL
Sampling variance of AL
Source
Berkey, C. S., Hoaglin, D. C., Antczak-Bouckoms, A., Mosteller, F, & Colditz, G. A. (1998). Meta-analysis of multiple outcomes by regression with random effects. Statistics in Medicine, 17, 2537-2550.
Examples
data(Berkey98)
#### ML estimation method
## Multivariate meta-analysis
summary( meta(y=cbind(PD, AL), v=cbind(var_PD, cov_PD_AL, var_AL),
data=Berkey98, I2=c("I2q", "I2hm", "I2am")) )
## Multivariate meta-analysis with "publication year-1979" as the predictor
summary( meta(y=cbind(PD, AL), v=cbind(var_PD, cov_PD_AL, var_AL),
x=scale(pub_year, center=1979), data=Berkey98,
RE.lbound=NA) )
## Multivariate meta-analysis with equality constraint on the regression coefficients
summary( meta(y=cbind(PD, AL), v=cbind(var_PD, cov_PD_AL, var_AL),
x=scale(pub_year, center=1979), data=Berkey98,
coef.constraints=matrix(c("0.3*Eq_slope", "0.3*Eq_slope"),
nrow=2)) )
#### REML estimation method
## Multivariate meta-analysis
summary( reml(y=cbind(PD, AL), v=cbind(var_PD, cov_PD_AL, var_AL),
data=Berkey98,
model.name="Multivariate meta analysis with REML") )
## Multivariate meta-analysis with "publication year-1979" as the predictor
summary( reml(y=cbind(PD, AL), v=cbind(var_PD, cov_PD_AL, var_AL),
x=scale(pub_year, center=1979), data=Berkey98) )