- De Witte, K, Maassen van den Brink, H & Groot, W. Efficiency of education in generating literacy.
- De Witte, K. (2009) Dropout from secondary education: Allâ€™s well that begins well.
- De Witte, K. and Marques, R. (2009), Gaming in a benchmarking environment. A non-parametric analysis of benchmarking in the water sector. MPRA Paper 14679.
- De Witte, K. and Marques, R. (2009), Influential observations in frontier models, a robust non-oriented approach to the water sector. mimeo.
- De Witte, K. and Rogge, N. (2009), Accounting for exogenous influences in a benevolent performance evaluation of teachers.
- Emrouznejad, A. and K. De Witte (2009), COOPER-framework: A Unified Standard Process for Non-parametric Projects. Aston University Working Paper.
- Groot, W. and H. Maassen van den Brink. Does the market of enterprise-related training work? An overview study (2009)
- Marques, R. and De Witte, K. (2009), Is big better? On scale and scope economies in the Portuguese water sector. mimeo.