The "Behavioural Insights team" within the UK government has achieved a relevant increase in tax returns by leveraging the psychological power of reciprocity in the process of the tax declarations. By putting a handwritten message on the the tax return saying: “This message is important” the "nudge unit" found that more people tend to deal with it. According to Unit Head David Halpern they are even able to quantify the economic benefit of this handwritten note to the UK tax payers.

"For every pound spent on paying someone to write on an envelope with such a message you get a £2,000 return in terms of paid tax."

About Nudging:

  • "Nudging" is basically about "designing" people's choices in order to “nudge” them toward better decisions.
  • the "Nudging" concept is based on a book written by Richard H. Thaler and Cass R. Sunstein called "Nudge: Improving Decisions about Health, Wealth, and Happiness". 
  • Five tricks or nudges HMRC uses to make you pay £210m extra - Telegraph