Deformed Zipf's law in personal donation

Department of Systems Science, School of Management, Beijing Normal University - Beijing 100875, PRC

Corresponding author: ygwang@bnu.edu.cn

Received: 30 September 2009
Accepted: 21 October 2009

Abstract

The power law or Zipf's law phenomena in human behaviors have been widely observed and attracted intensive attention. In this letter, a new evidence on personal donation is presented and analyzed. A sample of donation to the victims of Sichuan earthquake in 2008 demonstrates that donation distribution has a particular pattern. The upper part is governed by Zipf's law and the lower part exhibits a uniform distribution. We propose a theoretical model in which people's wealth distribution follows a power law, they are willing to donate a random part of their wealth and have preferences on some specific numbers. This model provides us not only a reasonable explanation on the empirical donation pattern but also an effective method to get access to large-scale personal-wealth distributions.