For example, in a recent paper, Shleifer and his co-authors measured government effectiveness by mailing letters to non-existent business addresses in 159 countries and measuring how long it took for the letters to be returned – or whether they were returned at all. They found that this indicator correlated very well with many other governance indicators.
比如，在最新论文中，施莱弗及其合作者测量了政府效率。他们向159个国家的不存在的地址投递信件，测量信件被退回（或是否会被退回）需要多长时间。他们发现，该指标与其他治理指标之间的相关性相当好。