Clustered mitigated fraction

Estimates mitigated fraction from clustered or stratified data.

Usage

MFClus(formula, data, compare = c("con", "vac"), trace.it = FALSE)

Arguments

formula: Formula of the form y ~ x + cluster(w), where y is a continuous response, x is a factor with two levels of treatment, and w is a factor indicating the clusters.
data: Data frame. See Note for handling of input data with more than two levels.
compare: Text vector stating the factor levels - compare[1] is the control or reference group to which compare[2] is compared
trace.it: Verbose tracking of the cycles? Default FALSE.

Value

a mfcluster data object

Details

Averages the U statistic over the clusters and computes MF from it. Clusters are excluded if they do not include both treatments.

Note

If input data contains more than two levels of treatment, rows associated with unused treatment levels will be removed.

Factor levels for treatments not present in the input data will be ignored.

Clusters with missing treatments will be excluded. See mfbootcluster or use trace.it to identify excluded clusters.

References

Siev D. (2005). An estimator of intervention effect on disease severity. Journal of Modern Applied Statistical Methods. 4:500–508

Author

MF-package

Examples

if (FALSE) { # \dontrun{
MFClus(lesion ~ group + cluster(litter), piglung)

#  Comparing vac to con
#
#  MF = 0.3533835
#
#  By Cluster
#     w  u         r n1 n2         mf
#  U 25 10 0.4000000  5  5 -0.2000000
#  K 12  2 0.2500000  4  2 -0.5000000
#  Z 16 10 0.8333333  3  4  0.6666667
#  D  3  2 1.0000000  1  2  1.0000000
#  N  1  0 0.0000000  1  3 -1.0000000
#  T  8  5 0.8333333  2  3  0.6666667
#  P  4  1 0.5000000  2  1  0.0000000
#  L  3  2 0.6666667  1  3  0.3333333
#  G 15  9 0.7500000  3  4  0.5000000
#  J 15  9 1.0000000  3  3  1.0000000
#  W  6  3 0.7500000  2  2  0.5000000
#  A  9  3 0.3333333  3  3 -0.3333333
#  X 12  6 1.0000000  3  2  1.0000000
#  F 13  7 0.7777778  3  3  0.5555556
#  S 21 11 0.9166667  4  3  0.8333333
#  H 14  8 0.8888889  3  3  0.7777778
#  Y  2  1 1.0000000  1  1  1.0000000
#  E  2  1 1.0000000  1  1  1.0000000
#
#  All
#        w  u         r n1 n2        mf
#  All 181 90 0.6766917 50 52 0.3533835
#
#  Excluded Clusters
#  [1] M, Q, R, B, O, V, I, C
} # }