There is a certain air of plausibility around the idea that school leavers should continue on to third-level education via a broad entry route. It makes intuitive sense that young people’s education should start out broad and get narrower as they get older and more mature.

Hence, advice like that given recently in The Irish Times, namely that "choosing a broad course, such as arts, law, commerce or science, is a good place to start", seems sensible.

But is this good advice for everyone?

The rationale for the broad-entry approach seems to be threefold. First, it will take the heat out of the CAO points race and, perhaps, make students learn more effectively at second level.

Second, it will make students less likely to choose the wrong course and fail to progress through the first year of college.

Third, it will allow students to make a more mature and informed choice about their ultimate field of specialisation.

The evidence for the first point is weak. Many of the courses with the highest points have the largest intakes.

A good example of this is the broad entry to science in UCD, which has an intake of about 400 students and minimum entry points of more than 500.

Look right across the system. Even within a single discipline such as engineering you will find there is no relationship between intake and minimum entry points.

CAO points are strongly influenced by the perceived prestige of an institution and, crucially, geographical factors. And the CAO system is not simply one of supply and demand; it is much more nuanced than that.

Niche points

It is worth pointing out that about 70 per cent of “niche” courses – those with an intake of 10 or fewer students – have minimum entry points below 350. Fewer than 5 per cent of niche courses have points above the elite 500-point mark.

Controlling the intake does not guarantee high points; low intake is usually a consequence of low demand.

As for the idea that broad entry will make students less likely to drop out of college: again, the evidence is simply not there.

Studies indicate that most students who drop out do so because they have “chosen the wrong course”.

Many observers seem to have concluded that choosing the wrong course is a consequence of the complexity of the CAO system, especially the sheer number of courses to choose from.

In fact, choosing the wrong course is more likely to be a direct result of students having a low CAO points score and being allocated a course that is very low down their list of preferences.

This means that they are probably not very interested in their “chosen” course and are probably not able for the academic challenges involved.

Indeed, a recent Higher Education Authority report demonstrates unequivocally that the best predictor of nonprogression is a lack of "prior educational attainment". The lower your points, the more likely you are to drop out.

More informed?

Still, won’t broad entry allow students to make more informed choices about their ultimate field of specialisation?

Maybe, but maybe not. The key word here is “choice”, and some institutions might not be in a position to guarantee students entry into their discipline of choice at the end of first or second year.

The simple reason for this is that capacity, especially in the laboratory sciences, is limited.

Therefore, with broad entry you risk exposing vulnerable first-year students to a high-pressure, highly competitive environment at the very time they are finding the transition from second to third level highly challenging.

When I attend careers events and talk to school leavers, I am often struck by the fact that we have two populations of students.

There are those who are mature, who have done their research, and who know quite well what they want to study at third level. The denominated entry system serves their needs well.

Then there are those who have only the vaguest idea of what they want to study. Broad entry might suit them better.

We need a mixed system, and just because some institutions might favour one approach does not mean that all institutions should follow suit.

We should not get ideological about this and we should not believe that tinkering with the CAO system will solve the many challenges facing the third-level system.

• Dr Greg Foley is a lecturer at DCU's school of biotechnology. He is currently serving a term as associate dean for teaching and learning in the university's faculty of science and health. He is writing here in a personal capacity