Print and summary method for Copas selection model

Description

Print and summary method for objects of class copas.

Usage

## S3 method for class 'copas'
print(x, sign.rsb=x$sign.rsb, backtransf=x$backtransf,
      digits=max(3, .Options$digits - 3), ...)

## S3 method for class 'copas'
summary(object, level=0.95, sign.rsb=object$sign.rsb, ...)

## S3 method for class 'summary.copas'
print(x, digits = max(3, .Options$digits - 3),
      backtransf=x$backtransf, header=TRUE, ...)

Arguments

Details

The summary.copas function prints a summary of a Copas analysis, performed using the function copas. It complements the graphical summary of the results, generated using plot.copas.

Specifically it prints a table where the:

first column corresponds to the x-axis in plots 3 & 4 from plot.copas;

second column corresponds to the treatment effect displayed in plot 3 from plot.copas;

third and fourth columns give the confidence intervals for this treatment effect,

fifth colum gives the p-value for an overall treatment effect,

sixth column gives the p-value for residual publication bias (the y-axis of plot 4 from plot.copas (see help(plot.copas) under plot 4 for a further explanation of this p-value))

seventh column gives an approximate estimate of the number of studies the model suggests remain unpublished if the probability of publishing the study with the largest SE is as in column 1.

Below this is displayed the results of the Copas analysis for the smallest degree of selection for which the p-value for evidence of residual selection bias exceeds sign.rsb (default: 0.1). This is simply extracted from the corresponding row in the table above.

Lastly, the usual random effects estimate (based on the DerSimonian-Laird method) and 95% confidence interval is printed.

The function print.copas prints the summary information above together with the following information:

Range of gamma0 values used (see help(copas));

Range of gamma1 values used (see help(copas));

Largest SE of all studies in meta-analysis;

Range of probability publishing trial with largest SE;

The next table gives details relating to the summary of the contour plot. Specifically, it gives details from fitting a straight line to each treatment-contour in the contour plot. Column 1 (headed level) shows the treatment-contours; column 2 (nobs) shows the number of observations used by the contour plot command within the copas function to plot this contour line; column 3 (adj.r.square) shows the adjusted r-square from fitting a straight line to this contour; columns 4 & 5 show the slope and its standard error from fitting a straight line to this contour.

Value

A list is returned by the function summary.copas with the following elements:

Author(s)

James Carpenter James.Carpenter@lshtm.ac.uk, Guido Schwarzer sc@imbi.uni-freiburg.de

See Also

copas, plot.copas metabias, metagen

Examples

##
## Load data
##
data(Fleiss93)
##
## Perform meta analysis, effect measure is odds ratio (OR)
##
meta1 <- metabin(event.e, n.e, event.c, n.c,
                 data=Fleiss93, sm="OR")
##
## Perform Copas analysis
##
cop1 <- copas(meta1)
summary(cop1, level=0.95)

Results