1. B. Augurzky, and C. Schmidt (2001 ), 'The Propensity Score: A Means to an End', Institute for the Study of Labour (IZA) Discussion Paper number 271, March, Bonn.
2. Exploring the relationship between performance management and program impact: A case study of the job training partnership act
3. D. Black, M. Berger, B. Noel, and J. Smith (1999 ), 'Is the Threat of Training More Effective than Training Itself?' Unpublished working paper, Version of 12 November 1999. Available at http://www.bsos.umd.edu/econ/jsmith/exl11299.PDF.