After nine years around a third of “domestic” PhD by research students are still studying or have given it away, according to Commonwealth completion data. (Thanks to the learned Andrew Norton for the pointer)

But more internationals stick at it, with completion rates nine years from starting ranging from 77 per cent to 84 per cent.

The figures are for 2007 to 2012 starts.

Group of Eight universities collectively improved over time, from 81 per cent completions for 2007 starters through to 88 per cent for those beginning in 2012.

The ATN group results were stable – ranging from 77 per cent in 2008 to 84 per cent for 2011 starters.

The Innovative Research Universities improved from 70 per cent for 2007 starts through to 77 per cent – 78 per cent from 2009.

The Regional Universities Network also improved from 53 per cent in 2007 to 67-68 per cent across the four most recent years.

STEM students consistently completed at a higher rate (middle 80 per cents) than HASS – 67 per cent to 77 per cent.