The most recent statistics show first-year attrition rates in Australian universities are at 15 per cent.
This has led to Education Minister Simon Birmingham's call for universities to take "responsibility for the students they enrol".
Attrition does not mean dropping out. It just means the student did not continue their study in the following year.
For example, attrition includes students who suspend studies due to personal circumstances, but return to study a later year.
However, the evidence is that most students who discontinue their studies do not end up completing.
How does Australia compare to other countries?
To analyse comparative performance, we looked at attrition rates in a number of countries, as well as regions within some countries.
As with Australia, most countries focus their attention on nationals (that is, not international students) entering university for the first time.
Australia's national attrition rate was 14.97 per cent, with institutions ranging as low as 3.92 per cent and as high as 38 per cent. The best-performing state was New South Wales and the worst was Tasmania. Of 39 institutions, 12 had an attrition rate over 20 per cent.
England, Wales, Northern Ireland, Scotland and Ireland all performed better than Australia.
Aotearoa, New Zealand, had an overall attrition rate of 16 per cent, slightly higher than Australia's. This was also the case with US public higher institutions offering four-year degrees, where the attrition rate was 17.7 per cent.
Universities in Ontario, which covers 40 per cent of Canada, had an average attrition rate of 12.8 per cent for full-time students. But the overall attrition rate (which includes part-time students) would likely place this figure even closer to Australia's attrition rate, though we can't say this for certain.
What causes student attrition?
Many things affect student attrition, including age, socio-economic status, location and time on campus.
Our study focused on three elements that have the potential to contribute to higher rates of attrition. The first is above-average student-to-staff ratios, as an indicator of student-lecturer interaction.
The second is above-average ratios of part-time enrolments, suggesting students are juggling study with work and personal commitments. The third is above-average ratios of external enrolments (such as students studying online), since these students have little or no access to the majority of on-campus support services.
The issues of part-time enrolments and external enrolments are closely related, as most students studying externally also study part-time.
We searched in the official higher education statistics for relationships between attrition and these three elements. That is, were attrition rates higher for universities that had more students per lecturer, or higher part-time enrolments, or more students studying externally?
We found some links between attrition rates and student-to-staff ratios. Some 15 universities had higher-than-average attrition rates when they also had higher-than-average student to staff ratios.
And nine universities that had better-than-average student-to-staff ratios also had better than average attrition rates.
But that still meant 15 universities bucked the trend. They either had better attrition despite having worse student-to-staff ratios, or the opposite.
There was a much stronger relationship between attrition rates and external enrolment ratios. Some 20 universities had below-average attrition and external enrolment rates, and 10 had above-average attrition and external enrolment rates.
The correlation was even stronger between attrition rates and part-time enrolments, with 31 universities displaying a direct relationship between the two factors.
Looking at our international comparisons, we saw similar trends. The overall attrition rate in the UK was 9.8 per cent. But this hid an attrition rate of 35.5 per cent for part-time students.
For those studying through the UK Open Universities (so, externally), the attrition rate was even higher, at 43.5 per cent.
In the US, the attrition rate for part-time students was 37.2 per cent. In New Zealand, it was 26 per cent.
What type of higher education system do we want?
Students who don't complete their courses are not only missing out on a personal opportunity, there's also lost potential to society.
Students and universities must aim to further reduce attrition. Universities are changing their admission, teaching and student support to increase their students' success. But completion rates also reflect what kind of higher education system we want.
That said, Australia's attrition rates are not unusually high by these international comparisons.
We should accept a modest level of attrition so we can keep providing opportunities for part-time students and others who don't fit the conventional mould.
Students studying part-time, especially those studying externally, need specialised support to help them balance their studies with their work and life commitments. But they don't need to see their opportunities for flexible study reduced, just so an institution can improve its retention rate.
Tim Pitman is a researcher in higher education policy at Curtin University.
Gavin Moodie is an adjunct professor at RMIT University.
Originally published in The Conversation