We might like to think we're not influenced by other people, but a new study into the group-buying mechanisms² - like those used on coupon³ sites such as Groupon and LivingSocial - reveals that telling buyers who come later to the offer how many have already signed up increases the number of purchasers.

我们也许认为我们不会受到他人的影响，但一项针对团购机制（正如Groupon和LivingSocial等团购网站的机制一样）的研究表明，告诉后来的买家已经有多少人报名参加能够增加购买者的人数。

Researchers at the University of Toronto's Rotman School of Management wanted to understand why group buying sites that have entered the market recently have enjoyed greater success than those operating a decade ago, such as Mercata and MobShop.

Earlier attempts typically left potential buyers waiting for days before confirming whether or not they had got the offer they had signed up for.

'We think one of the reasons group-buying has been successful recently is because of the short time horizon,' says Rotman Professor Ming Hu, who co-wrote the study with Professor Mengze Shi and PhD student Jiahua Wu. 'It allows for a herding⁴（集中畜群） effect.'

Another reason is the use of an information structure that discloses to later arrivals how many have already signed onto the deal.

Researchers looked at two ways of designing the purchasing mechanism¹ for a group buy: a simultaneous mechanism, where no one knows how many buyers have come before them, and a sequential（连续的） mechanism, where a second group of buyers has the advantage of knowing the size of the first group.

The researchers' analytical⁵ model shows the most successful mechanism is the sequential one because it eliminates uncertainty⁶ for those coming later to the deal, and improves the confidence of those who sign on early, as they're able to track the numbers of those who come after them.

'That boosts confidence,' says Professor Hu, who teaches operations management. Deals for "luxury" services, versus⁷ everyday items, work better in a group buy scenario⁸ because they offer consumers a greater benefit.