This study by Roger Harris, Michele Simons, Carmel McCarthy examines the nature of the training activity of private registered training organisations (RTOs) offered to Australian students in 2003, based on data from a national sample of 330 RTOs. The study also provides estimates of the private sector's overall contribution to the total vocational education and training (VET) effort in Australia for that year. Private providers are diverse and cover a wide variety of types. Generally they are small organisations offering a wide range of programs; both accredited and non-accredited. While there are some issues relating to data quality, it is clear they make a substantial contribution to the overall Australian VET effort. It is estimated that, in 2003, private RTOs had about 2.2 million students, which compares with 1.7 million students in the publicly funded sector in that year. However, comparisons with the public VET sector are problematic because there are no estimates available of the training hours delivered by private RTOs.