Last time you booked a hotel or restaurant, you may well have checked it out on TripAdvisor first. Whatever your price bracket, if a place was rated below about a three out of five, then the chances are you’ll have discounted it. The same goes when you buy a book on Amazon, or order an Uber.

Ratings are useful for consumers. After all, thanks to TripAdvisor, great restaurants in hidden-away locations can still thrive, and we rarely subject ourselves to books that are poorly researched or written. These advances can only be a good thing.

And yet, in education, where outcomes are infinitely more important, and children only ever get one chance, New Zealand has made an art out of obfuscation.

There can be no more powerful symbol of New Zealand’s refusal to call a spade a spade than the great befuddlement that is NCEA.

NCEA was originally conceived as a replacement for the old university-dominated trio of School Certificate, University Entrance and University Bursary. Growing discomfort with the old system’s insistence on only 50% passing every year, meant that the winds of progress and change began to blow.

NCEA, and the National Qualifications Framework (NQF) in which it sits, have come to symbolise that change. Nowadays our children inhabit a bright new era of flexibility, choice and more opportunities for success.

However, NCEA also marked a move away from rating students against one another, or any broadly-shared expectation of school success. Instead, NCEA measures students against a bounty of incomparable standards, with only the scrawniest skeleton of minimum requirements.

It is little wonder, therefore, that NCEA outcomes are difficult to understand.

On top of this, NCEA’s validity has been seriously challenged. The OECD’s PISA data indicates that the performance of New Zealand’s 15 year olds has fallen steadily in maths, reading and science since 2009. Over the same period NCEA Level 2+ achievement has risen from 68% to 79%.

Some argue that this disparity exists because PISA measures different things to NCEA. However, if our national assessment cannot help us infer even the most basic trends in reading and maths, not to mention comparative judgements, then what ultimately is the point of having it?

We would not trust TripAdvisor if it told us all hotels were rated five stars. So why should our children and employers trust a system that levels all differences that exist between subjects and students?