dat.raudenbush1985
study | numeric |
study number | author |
character |
study author(s) |
year | numeric |
publication year | weeks |
numeric |
weeks of contact prior to expectancy induction |
setting | character |
whether tests were group or individually administered | tester |
character |
whether test administrator was aware or blind |
yi | numeric |
standardized mean difference | vi |
numeric |
corresponding sampling variance |
In the following years, a series of studies were conducted attempting to replicate this rather controversial finding. However, the great majority of those studies were unable to demonstrate a statistically significant difference between the two experimental groups in terms of IQ scores. Raudenbush (1984) conducted a meta-analysis based on 19 such studies to further examine the evidence for the existence of the Pygmalion effect. The dataset includes the results from these studies.
The effect size measure used for the meta-analysis was the standardized mean difference (yi
), with positive values indicating that the supposed bloomers had, on average, higher IQ scores than those in the control group. The weeks
variable indicates the number of weeks of prior contact between teachers and students before the expectancy induction. Testing was done either in a group setting or individually, which is indicated by the setting
variable. Finally, the tester
variable indicates whether the test administrators were either aware or blind to the researcher-provided designations of the children's intellectual potential.
The data in this dataset were obtained from Raudenbush and Bryk (1985) with information on the setting
and tester
variables extracted from Raudenbush (1984).
### load data
dat <- get(data(dat.raudenbush1985))
### random-effects model
res <- rma(yi, vi, data=dat)
res
### create weeks variable where values larger than 3 are set to 3
dat$weeks.c <- ifelse(dat$week > 3, 3, dat$week)
### mixed-effects model with weeks.c variable as moderator
res <- rma(yi, vi, mods=~weeks.c, data=dat, digits=3)
res
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