| dat.normand1999 {metafor} | R Documentation |
Results from 9 studies on the length of the hospital stay of stroke patients under specialized care and under conventional/routine (non-specialist) care.
dat.normand1999
The data frame contains the following columns:
| study | numeric | study number |
| source | character | source of data |
| n1i | numeric | number of patients under specialized care |
| m1i | numeric | mean length of stay (in days) under specialized care |
| sd1i | numeric | standard deviation of the length of stay under specialized care |
| n2i | numeric | number of patients under routine care |
| m2i | numeric | mean length of stay (in days) under routine care |
| sd2i | numeric | standard deviation of the length of stay under routine care |
The 9 studies provide data in terms of the mean length of the hospital stay (in days) of stroke patients under specialized care and under conventional/routine (non-specialist) care. The goal of the meta-analysis was to examine the hypothesis whether specialist stroke unit care will result in a shorter length of hospitalization compared to routine management.
Normand, S. T. (1999). Meta-analysis: Formulating, evaluating, combining, and reporting. Statistics in Medicine, 18, 321–359.
### load data
dat <- get(data(dat.normand1999))
### calculate mean differences and corresponding sampling variances
dat <- escalc(measure="MD", m1i=m1i, sd1i=sd1i, n1i=n1i, m2i=m2i, sd2i=sd2i, n2i=n2i, data=dat)
dat
### meta-analysis of mean differences using a random-effects model
res <- rma(yi, vi, data=dat)
res
### meta-analysis of standardized mean differences using a random-effects model
res <- rma(measure="SMD", m1i=m1i, sd1i=sd1i, n1i=n1i, m2i=m2i, sd2i=sd2i, n2i=n2i,
data=dat, slab=source)
res
### draw forest plot
forest(res, xlim=c(-7,5), alim=c(-3,1), cex=.8)
text(-7, 11, "Study/Source", pos=4, cex=.8)
text( 5, 11, "Observed SMD [95% CI]", pos=2, cex=.8)