Undercover Economist

Why feedback can be just so much noise

Should managers be giving more frequent performance appraisals? Do “customer feedback” questionnaires serve any useful purpose? The answers are not obvious. A feedback-free environment is not conducive to learning new skills, but then again, feedback itself can be confusing or demoralising.

I suffered from both too little and too much feedback in my last year of school. That was when I decided to stop going to piano lessons, having been coasting lazily at a mediocre level for years. My piano teacher, who had maintained a tactful silence, wistfully remarked that I had a beautiful touch on the keyboard – better than any of her hard-working, virtuosic prodigies. I was not impressed. Had she said that five years earlier, I might have worked harder. (Or so I told myself.)

It was also the year that I decided to spend less time with my A-level Further Maths exercises and more time with my girlfriend. I judged that my modest mathematical skills would not deliver a grade I needed to get into university, which would have to come from some other subject. Getting a C was no more useful than getting an E. So I stopped working, duly got the E, and did indeed get into university by other means.

Apart from revealing a deep inner laziness, these anecdotes point out that feedback can cut both ways. My ongoing maths grades proved clearly to me that I was facing an insurmountable obstacle, so I gave up. But had the gap between my ability and my target been smaller, that feedback might have spurred me into action instead of into the arms of my girlfriend.

Furthermore, as Gary Klein points out in a thoughtful and wide-ranging new book on decision-making, Streetlights and Shadows, much of what we might think of as feedback is useless. We may discover that something we did went well, but not why. For a simple, oft-repeated task, that may be enough. But much of life is not like that, and simple feedback about outcomes will do nothing. Too much feedback, too soon, can also be counter-productive in the long run. We may learn quickly while the feedback continues, but when the trainer or manager disappears, we discover that we have no idea how to continue teaching ourselves.

Obviously, feedback is often just what is needed. A new research paper from Oriana Bandiera and Valentino Larcinese of the London School of Economics, and Imran Rasul of University College London, studies the effect on student performance of an accidental experiment. Bandiera and her colleagues realised that the MSc courses at a leading university all had the same basic structure (exams followed by a thesis) but for historical reasons – and apparently at random – some revealed the exam grades before the thesis was written, while others withheld information about all grades until the course was complete.

The results were surprisingly clear: feedback about their exam performance seemed to spur everyone on. Struggling students decided to pull their socks up; high-fliers were inspired to yet greater heights. The effect was roughly comparable to that of shrinking class sizes – but presumably a great deal cheaper to achieve.

I wonder, though, if Bandiera and her colleagues have really figured out the causal mechanism. In their theoretical model, the results make sense only if overconfident students put in more effort when unpleasantly surprised while diffident students work harder when given a boost. A more plausible explanation, it seems to me, is that uncertainty is paralysing for everyone.

And I wonder whether the results will carry over to the workplace. Honest appraisal is to be expected, eventually, in education. In the office, it can be awfully inconvenient for all concerned.

Also published at ft.com.