Alison Wolf

'I was, and am, utterly bemused by Oxbridge's arrogant belief that abandoning exams for interviews meant they would be "fair" to everyone'

The flawed interview process is no substitute for public examination based on strict criteria

Examinations have had a consistently bad press of late. They stress out our children, who sit them in ever-increasing numbers. They distort teaching and learning. Worse, they get mis-marked and misgraded, and people's lives get ruined in the process.

All more or less true: but this, nonetheless, is a column in praise of examinations. They may not be perfect but look at the alternatives.

The tide of expert opinion has run against examinations for a long time.

Back in 1988, when the government introduced the national curriculum and "key stage" testing at ages 7, 11 and 14, the panel developing the system argued strongly against conventional paper-and-pencil tests. Within universities, any move away from the examination hall is seen as "progressive", encouraging a more valid assessment of achievement and more genuine learning by the student. The vocational education reforms associated with NVQs assumed that examinations of vocational skills were inherently invalid and must be replaced by direct observation of practice.

Before being accused of Gradgrind tendencies ("FactsI facts alone are wanted"), let me emphasise that I certainly believe in variety in the way we assess students: in extended projects, GCSE coursework components, and testing oral language and lab skills. But I also believe, when high-stakes decisions are made, in giving first priority to fairness and due process.

On that score, formal examinations deserve praise, not blame.

In most of life, people get chosen for competitive positions on just one of two bases: formal evidence from tests and qualifications, or interview. If everyone has the same qualification, you can, as they do for a few Dutch university courses, have a formal lottery; or you could use a pin. As for handing out qualifications, the basic choices are between public examinations, where marking criteria are common across the group and can be checked, or largely unaudited teacher judgement. I know how I would want my own fate decided.

Interviews carry weight because interviewers are almost uniformly convinced that they can judge character and ability. However, the evidence is uniformly against them. In predicting future performance, interviews overall add nothing, or almost nothing, to what other formal measures tell us, and predictions made on the basis of interviews are often wrong.

Studies of the careers of recruits to large organisations show that a single letter-drafting exercise is worth a multiplicity of interviewers' reactions.

Different interviewers tend to disagree about the characteristics and capability of candidates. General preconceptions are also important.

Interviewers who expect applicants to be mostly of high calibre tend to give all applicants higher ratings than do interviewers whose general expectations are low; and we all tend to approach interviews with a mental model of the "typical" interviewee. There is also strong evidence of "contrast" effects, meaning that if an average candidate is preceded by a couple of highly qualified, or very weak, ones, there are strong effects (down or up) on interviewers' reactions. People also tend to make up their minds very early in an interview, so early questions carry disproportionate weight.

Lecturers and teachers can at least discuss and share student work with colleagues before passing judgement. Even so, those judgments are heavily influenced by the particular groups they teach. If their standard is generally low, average work comes to be seen as very good, and vice versa.

For UK public secondary examinations, teacher-assessed work contributes only a limited part of the mark. National benchmarks are critical, and they also help teachers with their own marking. In our increasingly modularised university degrees, however, the comparison (and the marking) group can be very small and atypical. As for interviews and oral examinations, if these are a poor basis for high-stakes decisions when candidates are all meeting the self-same panel, how much worse when institutions pool results from completely different interviewers, all with different questioning techniques and expectations.

All of this, given the time of year, brings us to university, and especially Oxbridge, entrance interviews. I was, and am, utterly bemused by these universities' arrogant belief that abandoning exams for interviews meant they would be "fair" to everyone. Many people predicted that the result would be an increasingly disputed admissions procedure - and how right they were. But the lesson is a general one. Personal judgements are no way to make high-stakes decisions about people's lives. The Chinese invented formal examinations for an excellent reason.

Alison Wolf is professor of education at the Institute of Education, London.