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Identify unique contrasts within a network that make up all the head-to-head comparisons. Repetitions of the same treatment comparison are grouped together.





A data frame containing variables studyID and treatment (as numeric codes) that indicate which treatments are used in which studies.


A data frame of unique comparisons in which each row represents a different comparison. t1 and t2 indicate the treatment codes that make up the comparison. nr indicates the number of times the given comparison is made within the network.

If there is only a single observation for each study within the dataset (i.e. as for standard network meta-analysis) nr will represent the number of studies that compare treatments t1 and t2.

If there are multiple observations for each study within the dataset (as in time-course MBNMA) nr will represent the number of time points in the dataset in which treatments t1 and t2 are compared.


data <- data.frame(studyID=c(1,1,2,2,3,3,4,4,5,5,5),

# Identify comparisons informed by direct and indirect evidence
#> # A tibble: 6 × 3
#> # Groups:   t1, t2 [6]
#>      t1    t2    nr
#>   <dbl> <dbl> <int>
#> 1     1     2     2
#> 2     1     3     1
#> 3     1     4     1
#> 4     2     3     1
#> 5     2     4     1
#> 6     3     4     1