DEA results graphic

[Robert Kolesar]

Hello, I am completing a Data Envelopment Analysis in Stata and want to graph the results and overlay the production frontier. Could you please provide some guidance on how I can go about doing this?

I am actually enrolled in the NetCourse 120/Statistical Graphics for Stata, but the instructors are unresponsive and/or do not know how do create this type of graphic.

Thanks, Robert

[Scott Merryman]

It is one example:

clear
input str2 firm dmu q x1 x2 
"A" 1 1 2 5 2 
"B" 2 2 2 4 1 
"C" 3 3 6 6 2 
"D" 4 1 3 2 3 
"E" 5 2 6 2 3 
end
dea x1 x2 = q

gen x1q = x1/q
gen x2q = x2/q
mat theta = results[1...,2]
svmat theta
gen FrontierX1 = theta*x1q
gen FrontierX2 = theta*x2q

twoway  line FrontierX2 FrontierX1, mc(black) lc(gs9) lw(thick) mlabv(firm) /// 
/* Extend lines of frontier*/  ///
|| scatteri 1 3 1 5, recast(line) lc(gs10) lw(thick) ///
|| scatteri 2.5 1 5 1, recast(line) lc(gs10) lw(thick) /// 
/*Scatter DMU */ /// 
|| scatter x2q x1q , xlabel(0(1)5) ylabel(0(1)5) mc(black) /// 
 mlab(firm) mlabcolor(black) mlabpos(2) ///
/* Farrell measure of technical efficiency */ ///
|| scatteri 0 0 5 2, ms(.) recast(line) lp(dash) lc(black) ///
|| scatteri 0 0 2 2, ms(.) recast(line) lp(dash) lc(black) /// 
|| scatteri 0 0 2 3, ms(.) recast(line) lp(dash) lc(black) /// 
|| scatteri 1.666 1.6666 "C'" , mlabcolor(black) mc(black) ms(Oh) msize(medlarge) ///
|| scatteri 2.5 1 "A'", mlabcolor(black) mc(black) ms(Oh) msize(medlarge) /// 
|| scatteri 1.429 2.142  "D'", mlabcolor(black) mc(black) ms(Oh) msize(medlarge) /// 
 || ,legend(off) ylabel(,angle(0)) xlabel(,grid) ///
title(CRS Input Orientated DEA Example) xtitle(X{subscript:1}/Q) ///
ytitle(X{subscript:2}/Q)  note("Note, firm A has input slack")

[Robert Kolesar]

Hello Scott- this is GREAT! I am getting stuck on mat theta, however:


. mat theta = results[1...,2]
results not found
r(111)

I am thinking that there must be some kind of storage issue with my results, but can't figure it out.

Robert

[Scott Merryman]

I dropped the line saving the returned results from dea:

mat results = r(dearslt)

which should come before the mat theta = results[1...,2]

[Robert Kolesar]

DEAgraph.gph

Thanks a ton! I was able to produce the attached graph which is fairly close to your example. Much appreciated.

Robert

[Marisa Foraci]

Thanks a lot for this Robert and Scott. I get somehow stuck at Extend lines of frontier and cannot proceed further. Error details copied below!!
scatteri 1 3 1 5, recast(line) lc(gs10) lw(thick) unrecognized command: scatteri r(199); Any idea of what I am doing wrong? Marisa

[Nel Schmidt Cornejo]

Marisa Foraci, I have the same problem with the graph, can anyone give us a hint how to do it? Thank you in advance.

[Suraj Thapa]

I feel like you already know it. Just type twoway scatteri ....
Also, do you guys know how do I get the final plot?

[Nel Schmidt Cornejo]

Hello Scott Merryman, sorry for the inconvenience, I want to ask you what varies in a DEA graphic with two inputs and three outputs?

[Nel Schmidt Cornejo]

Taking the example that you gave to Robert Kolesar

[Nel Schmidt Cornejo]

I did your example without problems

[Scott Merryman]

Nel Schmidt Cornejo, I do not know how you would graphically depict three outputs and two inputs in such a graph

[Fahad Mirza]

Just a small question. How would you go about visualizing if there is one input?

[Robert Kolesar]

You could show the ratio of input1 to output1 on the y-axis and the ratio of input1 to output2 on the x-axis. If you need to show more than 2 outputs in the graph then you could aggregate similar units using weights (prices, relative prices, etc...) and plot input1 on the y-axis and the aggregate outputs on the x-axis.