What is the best way to measure deprivation among students?

The Scottish government wants a fifth of university students to come from the most disadvantaged parts of the country by 2030.

The headline measure being used is the applicant's postcode area.

This is based on data from the Scottish Index of Multiple Deprivation (SIMD), which highlights the challenges facing the area - including income, poverty and unemployment.

But, of course, it does not follow that the applicant who lives in such an area is disadvantaged personally.

Earlier this month it emerged that a very small number of university students from the 20% most deprived areas (SIMD 20) had attended independent schools.

This meant that they would count towards a university's numerical target to widen access, although there is no suggestion that the applicants were given any special help to get in.

So if SIMD 20 is an imperfect measure, is another broad brush measure available instead?

There are no simple answers.

Parental income

This may sound fairer but is potentially more complicated than it sounds.

Current parental income could be misleading as a measure of a disadvantaged upbringing. The main breadwinner may have recently lost their job or retired.

It would also mean applicants having to provide information to the university admissions service which they do not currently have to give.

Eligibility for free school dinners

This certainly would indicate financial disadvantage. However some older children may not take up free school meals.

Coming from a single parent family

To directly equate the fact a child only lives with their mother or father with disadvantage almost sounds like moralising.

Many single parents who are widowed, divorced or whose long-term relationship broke up would almost certainly resent any implication that their child was disadvantaged by this factor alone.

Obviously some children who grow up in single parent families do face genuine hardship and disadvantage. There are very real issues, for example, surrounding the availability of childcare to allow a single parent to return to work.

But, of course, other single parents hold down good jobs and are able to rely on their extended family, friends or professionals to provide additional childcare.

Living in rented accommodation

Living in a rented house should not be confused with living in temporary or substandard accommodation or living on a "sink estate".

By historic standards, a relatively large proportion of Scots now own their own homes. In the 1980s and 90s, many became the first in their families to own property when they bought their council house. Before then many who lived in the best council houses might have been thought of as "skilled working class" or "lower middle class".

However that does not mean for a moment that someone who lives in social housing today could automatically be considered disadvantaged.

In some places, the price of property would make it hard for many people with good jobs to buy a home. Meanwhile the right to buy council houses has been abolished.