*! version 1.0.2 13 Dec 2009
help dea

Title

dea -- Data Envelopment Analysis in Stata

Syntax

dea
[if] [in]
[,
options]

Main
rts(string) specifies the returns to scale. The default is rts(crs), meaning the constant returns to scale. rts(vrs) and rts(drs) mean the variable returns to scale
and decreasing returns to scale.

ort(string) specifies the orientation. The default is ort(i), meaning the input oriented Data Envelopment Analysis(DEA). ort(out) means the output oriented DEA.

stage(#) specifies the way to identify all efficiency slacks. The default is stage(1), meaning the one-stage DEA. stage(2) means the two-stage DEA.

trace lets all the sequences and results displayed in the result window be saved in the "dea.log" file.

saving(filename) specifies that the results be saved in filename.dta.

Description

dea selects the input and output variables from the user designated data file or in the opened data set and solves Data Envelopment Analysis(DEA) models by options specified.

There are several options to enhance the models. The user can select the desired options according to the particular model that is required.

The dea program requires initial data set that contains the input and output variables for observed units.

Variable names must be identified by prefix¡°i_¡± for input variable and by ¡°o_" for output variable to allow that dea program can identify and handle the multiple input-output data set.
And the variable name of Decision Making Units(DMUs) is to be specified by "dmu".

The program has the ability to accommodate unlimited number of inputs/outputs with unlimited number of DMUs. The only limitation is the memory of computer used to run dea.

The result file reports the informations including reference points and slacks in DEA models.
These informations can be used to analyze the inefficient units,
for examples, where the source of inefficiency comes from and how could improve an inefficient unit to the desired level.

sav(filename) option creates a filename.dta file that contains the results of dea including the informaions of the DMU, input and output data used,
ranks of Decision Making Units(DMUs), efficiency scores, reference sets, and slacks.

The log file, dea.log, will be created in the working directory.

Examples

. dea

. dea,rts(vrs)

. dea,rts(vrs) ort(o)

. dea,rts(vrs) ort(o) stage(2)

. dea,rts(vrs) ort(out) stage(2) sav

. dea,rts(vrs) ort(o) stage(2) sav(dea1_result)

Saved Results

Matrix:

r(dearslt) the results of dea that have observation rows of DMUs and variable columns with input data, output data, efficiency scores, references, slacks, and more depending on the models specified.

Author

Yong-bae Ji and Choonjoo Lee

Korea National Defense University

Seoul, Republic of Korea

E-mail: [choonjoo lee]sarang64@snu.ac.kr