deaR (version 1.4.1)

is.friends: Friends check.

Description

Checks whether a subset of DMUs is friends or not, according to Tone (2010).

Usage

is.friends(datadea,
             dmu_eval = NULL,
             dmu_ref = NULL,
             rts = c("crs", "vrs", "nirs", "ndrs"),
             tol = 1e-6)

Value

Returns TRUE if dmu_eval is friends of dmu_ref, and FALSE otherwise.

Arguments

datadea

The data, including n DMUs, m inputs and s outputs.

dmu_eval

A numeric vector containing the subset of DMUs to be checked. If NULL (default), all DMUs are considered.

dmu_ref

A numeric vector containing which DMUs are the evaluation reference set. If NULL (default), all DMUs are considered.

rts

A string, determining the type of returns to scale, equal to "crs" (constant), "vrs" (variable), "nirs" (non-increasing) or "ndrs" (non-decreasing).

tol

Numeric, a tolerance margin for checking efficiency. It is 1e-6 by default.

Author

Vicente Coll-Serrano (). Quantitative Methods for Measuring Culture (MC2). Applied Economics.

Vicente Bolós (). Department of Business Mathematics

Rafael Benítez (). Department of Business Mathematics

University of Valencia (Spain)

References

Tone, K. (2010). "Variations on the theme of slacks-based measure of efficiency in DEA", European Journal of Operational Research, 200, 901-907. tools:::Rd_expr_doi("10.1016/j.ejor.2009.01.027")

See Also

maximal_friends, model_sbmeff

Examples

data("PFT1981")
datadea <- make_deadata(PFT1981,
                        ni = 5,
                        no = 3)
subset1 <- c(15, 16, 17, 19) # Subset of DMUs to be checked
result1 <- is.friends(datadea = datadea,
                      dmu_eval = subset1,
                      dmu_ref = 1:20) # We only consider a cluster formed by the first 20 DMUs
subset2 <- c(15, 16, 17, 20) # Another subset of DMUs to be checked
result2 <- is.friends(datadea = datadea,
                      dmu_eval = subset2,
                      dmu_ref = 1:20) # We only consider a cluster formed by the first 20 DMUs