Create a DEA data object

Builds a validated dea_data object from a data frame, classifying columns into inputs and outputs. By default columns are recognised by an i_ prefix (inputs) and an o_ prefix (outputs); the prefixes are stripped from the stored names for display. Columns can also be selected explicitly via inputs/outputs, which overrides the prefixes. Any remaining column is treated as metadata; a non-numeric one (or an explicit id) supplies the DMU labels.

Usage

dea_data(data, inputs = NULL, outputs = NULL, id = NULL)

Arguments

data

A data frame (or object coercible to one) with named columns: at least one input column and one output column.

inputs, outputs

Optional column selectors (character names or integer positions). When supplied they take precedence over the i_/o_ prefixes. A column may not be assigned to both.

id

Optional single column (name or position) holding DMU labels. If NULL, the first unclassified non-numeric column is used, falling back to the row names. Numeric id columns (e.g. integer DMU codes) are not auto-detected, because they cannot be told apart from an input or output that lacks an i_/o_ prefix; name such a column here explicitly.

Value

An object of class dea_data: a list with components

X

numeric matrix of inputs (one row per DMU).

Y

numeric matrix of outputs (one row per DMU).

labels

character vector of DMU labels.

See also

compute_efficiency, as_dea_data

Examples

df <- data.frame(
  city  = c("A", "B", "C"),
  i_lab = c(10, 12, 9),
  i_cap = c(5, 6, 4),
  o_gdp = c(100, 130, 90)
)
dea_data(df)
#> <dea_data>
#>   DMUs    : 3
#>   Inputs  : 2 (lab, cap)
#>   Outputs : 1 (gdp)

# explicit selection, no prefixes needed:
df2 <- setNames(df, c("city", "lab", "cap", "gdp"))
dea_data(df2, inputs = c("lab", "cap"), outputs = "gdp", id = "city")
#> <dea_data>
#>   DMUs    : 3
#>   Inputs  : 2 (lab, cap)
#>   Outputs : 1 (gdp)

# numeric DMU id codes must be named explicitly:
df3 <- data.frame(dmu = 1001:1003, i_x = c(2, 3, 4), o_y = c(1, 2, 2))
dea_data(df3, id = "dmu")
#> <dea_data>
#>   DMUs    : 3
#>   Inputs  : 1 (x)
#>   Outputs : 1 (y)