The Times Higher Education-QS World University Rankings are probably the most contentious - and the most widely read - feature we publish. They are liked and loathed in equal measure. "We absolutely love the world rankings when we've done well and ignore them when we've done badly," was how one vice-chancellor (who, incidentally, will be pretty pleased this year) summed it up.

This is the fifth year we have published the rankings and the methodology has remained unchanged for the past two. Along with our partners in the venture, Quacquarelli Symonds, we make enormous efforts to ensure that our quality-control processes and anti-cheating mechanisms are as robust as possible.

We try to ensure that the results are produced with a large amount of data. For example, there were more than 6,000 participants in the academic survey alone, producing an average of 20 responses per head. That is a staggering 120,000 data points, making it the largest known survey of university quality.

This is the only ranking that exists of universities overall; our closest competitor, the Shanghai Jiao Tong, concentrates on scientific research.

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These rankings are becoming increasingly important. They influence government spending and policy. Germany is putting more money into a small number of research universities in the hope of increasing their world standing. The rankings also affect university strategy. Dozens of institutions, especially in Asia, gear their strategy towards a Top 100 placing.

We are well aware of the responsibility this puts on us. But in compiling them, we are not encouraging universities to do anything that they should not be doing already.

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Providing good-quality teaching, attracting high numbers of international staff and students, having a good citations count and a reputation for excellence among their peers and among the employers recruiting their students should be at the heart of their mission. If we play any part in getting universities to raise their game, we are proud to do so.

We believe it is important that the rankings are published by Times Higher Education. We are independent; we have no affiliation to any university. We have no interest in the rank of any institution. And most importantly, as a magazine we do not serve the consumer but the higher education community.

Although confident of the strength of our methodology, we do not pretend that these rankings are perfect. For example, the tables make use of citations data known to our supplier, Scopus, on 23 June. Scopus has since added a large number of new sources to its database, which has already sparked some debate about our measurements. But the data for every institution were collected at the same time. We always welcome suggestions for improvements.

Critics argue that they are a blunt instrument, and they are right. But in many cases, they may be the only measure many students and university staff have.

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For students, they provide a good starting point for making a decision that will determine their future. And for ambitious staff operating in an increasingly globalised university world, they offer a snapshot of an institution's place in the world market.

For 2008, we congratulate Harvard University for its success in topping the rankings yet again. However, it is worth remembering that its endowment now totals more than $35 billion (?19 billion), roughly equivalent to the total income received by the entire UK sector last year. By that measure, the UK, with its 29 institutions in the Top 200 (and four in the Top 10), can stand proud on the world stage.