Portela, MariaThanassoulls, Emmanuel2011-09-082011-09-082004PORTELA, Maria; THANASSOULIS, Emmanuel - Malmquist indexes using a geometric distance function (GDF). In 4th International Symposium On DEA: Data Envelopment Analysis And Performance Management, Birmingham, United Kingdom, 5-6 September, 2004. – In [Proceedings of the] Data Envelopment Analysis and Performance Management. Aston Business School, 2004. p. 231-238http://hdl.handle.net/10400.14/5284Traditional approaches to calculate anal factor pmthwtivity change through Malmquist indexes rely on distance fin chaos. In this paper we show that the use of distance Junctions as a means to calculate total factor productivity change 'nth, introduce some bias in the analysis. and tnerefire tee propose a procedure that calculates total factor productivity change through observed values only. Our total factor productivity change is then decomposed into efficiency change, technological change, and a residual effimt. This decomposition makes use of a non-oriented measure in (E yler to avoid problems associated with the traditional use of radial oriented measures. especially when variable returns to seale technologies are to be compared.engconference object