Should we use the OECD’s analysis of the private financial benefits of tertiary education?

I’m quoted this morning in The Australian‘s report on graduate earnings across the OECD, which is in the latest issue of Education at a Glance.

The reported numbers seemed low compared to work Grattan and others have done for higher education, and I have had a bit more time since to work out why.

An issue I noted in the Oz is that the analysis included people with diplomas. In 2012, diploma holders were 28 per cent of everyone with a diploma or higher qualification. Their lower average earnings will bring down the overall average.

Another issue is that the OECD’s data source may be understating graduate income. They used a source I had never heard of for analysing educational returns, the ABS Disablity, Ageing and Carers survey. It was a general population survey so the issue is not that it is a sample of graduates with a disability. However, looking at the way the unit record data is made available to researchers it seems income is only available in ranges, the top one of which is $1,730 a week or more. We hit this problem in the 2011 census as well, with their top range of $2,000 a week or more. 11 per per cent of diploma holders, 21 per cent of bachelor degree holders, and 33 per cent of postgraduate degree holders reported incomes of $2,000 a week or more. As some of these would have incomes well over $2,000 a week, the average is artificially held down by the income category cap.

The OECD numbers are net present value, which means that income expected to be received in the future is counted as of less value than income received now. There is plausible time value of money theory for discounting the future – for example, an 18 year old prospective student would probably rather receive $1,000 now than $1,100 when they finish their 3 year degree, even though there is a favourable implied interest rate on offer.

But in our Graduate Winners report that was not the way we presented the data, which we left undiscounted in the key sections. This was partly because the undiscounted number is easier to understand, and partly because despite the plausibility of time value of money theory in various contexts I was not sure it was so persuasive in this one. In my view, one reason people pursue higher education is so that they will have a good job and a high income in 30 years time. How much theoretical sense does it make to heavily discount the value of achieving a major objective?

Some interesting data on male hourly earnings by years of experience from the latest HILDA report highlights this issue. For the first five or so years, male graduates don’t earn much more per hour than men with vocational education. But after that time a wide earnings gap develops – in the later years that are most discounted by the OECD methodology.

male hourly earnings

The discounting also affects another issue, which is that they assume students don’t work while studying, and the consequent assumed forgone earnings appear with a low discount and are deducted from gross earnings. But in Australia most students work while studying, so the forgone earnings cost is exaggerated, while future income benefits are under-valued.

There is no perfect method of doing educational returns analysis, and every data source in Australia has limitations. But overall I think the OECD numbers are less useful than existing Australian research on the financial benefits of education.

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