CCR model reports higher efficiency score in analysis than SBM, is it because CCR ignored slacks and SBM consider slacks?
Dear Adnan Abbas,
the results of DEA (non-SBM) and DEA-SBM with same return to scale must be same.
are you sure you are running the models right?!
@ Khalili: I am certain that I run the models accurately, but how can it be same if CCR ignore the slacks and SBM captured slacks.
It can be a software mistake.
So use SBM just to evaluate slacks for each DMU, and CCR or Super-efficiency model to get efficiency scores.
@ Gonchurak; Alright sir I got your poin, thanks for valuable contributio.
Thanks
@ Gonchurak , do i have a free access to SBM software? Thank you in advance.
Evangelia, yes, indeed. But some of them can be restricted. Full versions mainly are commercial.
I do not seem to understand clearly the discussion here. But CCR efficiency scores (using the traditional radial measurement approach) only consider radial slacks in the scores (Farrell 1957 definition of efficiency). The SBM is a non-radial measure that takes into consideration both the radial and non-radial slacks (Koopmans 1951 definition of efficiency).
As such, it is expected that the SBM will be more discriminatory than the CCR model. It is expected that the inefficiency scores for the CCR will be higher (at least for for input orientation) than the SBM scores. Even if you read Tone (2001):
Theorem 1. under Definition 3 states that: The optimal SBM score is not greater than the optimal CCR score.
Theorem 2. under Definition 3 states: A DMU is CCR efficient if and only if it is SBM efficient.
So the simple answer (in my view) to your question is YES
Tone, K. (2001). A slacks-based measure of efficiency in data envelopment analysis. European Journal of Operational Research, 130(3), 498-509.
Farrell, M. J. (1957). The measurement of productive efficiency. Journal of the Royal Statistical Society Series A: General, 120(3), 253–290.
Koopmans, T.C. (1951). An analysis of production as an efficient combination of activities. Activity analysis of production and allocation. T.C. Koopmans. New York, Cowles Commission for Research in Economics, Monograph No. 13, Wiley.
For software, there are a number of packages in R/R Studio that can run both
Thank you Turkson for your detailed and comprehensive input. I am very grateful. Kind regards
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