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Categorical variable

A factor which can assume only a predefined set of discrete values. Categorical variables are frequently used to indicate the presence or absence of an attribute. An analysis on fast-food restaurants could use a categorical variable assigned to I to indicate the presence of a drive-in window, with the value O denoting its absence. The use of categorical variables requires modifications in DEA models as indicated in Banker and Morey (1986). See also: ordinal variable.

– Banker R D and Morey R (1986) ‘The use of categorical variables in data envelopment analysis’, Mgmt. Sci., 32, pp 1613-1627.


DEA results are biased

Generally speaking, the results are biased if they favour a particular unit and/or unfairly assess the efficiency of some inefficient units. Although the actual DEA technique can be considered fair, bias can be introduced into the analysis through the omission of a critical factor or a lack of homogeneity in the field.

7th North American Productivity Workshop, June 6-9 – 2012, Houston, Texas

VII North American Productivity Workshop
June 6-9 – 2012
Rice University, Houston, Texas

for further information please see

The 8th Asia-Pacific Productivity Conference, July 25-27, 2012, KMITL, Bangkok, Thailand

The 8th Asia-Pacific Productivity Conference, July 25-27, 2012, KMITL, Bangkok, Thailand
for further detail splease see:

DEA Symposium, February 20-21, Japan

DEA (Data Envelopment Analysis) Symposium 2012 will take place at Seikei University in Tokyo from February 20th to 21st, 2012, celebrating the 100th anniversary of Seikei Gakuen.
For further details please see:

DEA2011,Thessaloniki, Greece, August 2011

DAE2011 Thessaloniki – Greece August 2011


DEA2010,Beirut, Lebanon, June 2010

DEA2010 Beirut, Lebanon June 2010


DEA2009, Philadelphia, USA, July 2009

DEA2009 Philadelphia, USA July 2009


DEA2007, Hyderabad, India, January 2007

DEA2007 Hyderabad, India January 2007


DEA2004, Birmingham, UK, September 2004

DEA2004 Birmingham, UK September 2004


goin up