*! version 1.1 8jun2015

Title

network convert -- Convert network data between formats

Syntax

network convert
augmented|standard|pairs
[,
options]

Options available when converting to augmented format
large(#) Value used for variance of contrasts with the reference treatment in trials without the reference treatment.
Default value is 100000.
If errors occur, it may be worth decreasing this parameter.
If discrepancies occur, for example between different formats,
then it may be worth increasing this parameter.

ref(trtcode) Changes the reference treatment.

Description

network convert converts between the
three formats described in help network.

Details of conversion to augmented format

For studies lacking a reference treatment arm,
conversion to augmented format requires an augmentation procedure which is different
from that performed by network setup
(and which therefore gives a different augmented dataset, and very slightly different analysis results).
Suppose the reference treatment is A and we want to convert a BCD study from standard format.
We know the estimates, variances and covariance of the C-B and D-B contrasts, because B is the first treatment in this study.
Let L be the large number specified by the large() option.
We augment by assuming that the B-A contrast is zero with variance L and is uncorrelated with the B-C-D contrasts.
This gives the following procedure:

(1) the C-A contrast equals the B-A contrast;

(2) the variance of the C-A contrast equals the variance of the C-B contrast plus L;

(3) the covariance of the C-A and D-A contrasts equals the covariance of the C-B and D-B contrasts plus L.

Examples

. network convert pairs

. network convert standard

. network convert augmented, large(1000) ref(C)

Return to main help page for network