PIT people against each other, and they may just show their best. That is the idea behind incentive contests which aim to jump-start a stagnating field to eke out improvements. Such contests offer prizes that range from hundreds to millions of dollars. They are meant to recruit non-conventional participants with expertise from other domains, providing fresh insights and spurring existing researchers to get on their bikes.

The latest entrant in this field is the Heritage Health Prize. The $3m award will go to whoever does the best job of improving predictions about which patients in a model set are most likely to require a visit to hospital within the next year. Such predictions would allow early interventions, pre-empting costly hospitalisations. The grant, funded by Richard Merkin, the boss of Heritage Provider Network, a healthcare firm, is similar in size to the X Prize Foundation's awards (to which Mr Merkin also chips in). He expects to use the results to improve care and lower costs. The competition will run for two years, with $230,000 in milestone prizes. A $500,000 consolation prize will be awarded if competitors fail to reach the target for efficiency gains, which has yet to be set.

The X Prizes tend to focus on spectacular feats of human endeavour. It began with the Ansari X Prize: $10m to the first private-sector group able to fly a reusable spacecraft 100km (62 miles) into space twice within two weeks. It was won in 2004 by a team led by Burt Rutan, a pioneering aerospace engineer, and Paul Allen, a co-founder of Microsoft. Current contests focus on big technological challenges like cleaning up after oil spills or sequencing genomes.

To manage the Heritage venture, Mr Merkin turned to Kaggle, a startup which organises computing contests. Its competitions resemble the one made famous by Netflix, in which the movie-lender awarded $1m in 2009 to a team that improved the accuracy of its recommendation algorithm, though Kaggle's prizes typically range from a few hundred to a few thousand dollars. Entrants, who include computer scientists, statisticians, other academics, as well as knowledgeable amateurs, are given a large, historical set of data to crunch. Their submissions are then judged against data for a later period which have not been made public. In one ongoing project the company is working with Deloitte, a consultancy, and the World Chess Federation which are offering $10,000 to anyone who comes up with the best way to improve the algorithm used to rank players. The present system, called Elo, is also used in other disciplines, including football and online gaming, so any improvements may extend beyond the royal game. The current leader, a Dutch PhD candidate, has already improved accuracy by a quarter.

While the scale of the Heritage award far exceeds Kaggle's current competitions, the principles remain the same. Interestingly, the amount of money on offer does not seem to correlate with the number of entrants, according to Anthony Goldbloom, Kaggle's boss (and a former intern in this newspaper's Finance and Economics section). To attract participants the challenge must be interesting and approachable. There is no point setting a problem which would require supercomputers to solve, since few people have access to such kit. An ordinary laptop is enough to sift through the Heritage data, as Mr Goldbloom demonstrated at the Data 2.0 conference last week. In the first few days, thousands have downloaded the competition database.

Another key feature is to let contestants know how well others are faring. The Heritage prize specifically requires milestone winners to disclose their algorithms, but participants tend to share information of their own accord. Those who fail to do so are often derided as "spongers".

Most competitions follow a similar script: entrants make strides until they hit a hard limit beyond which they proceed at a much slower pace. But by then substantial progress far beyond previous plodding work will typically have been made. Mr Merkin will be hoping that this holds as true for healthcare as it does for movie rentals.