@techreport{NBERw5435,
 title = "Working for Nothing: The Supply of Volunteer Labor",
 author = "Richard B. Freeman",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "5435",
 year = "1996",
 month = "January",
 URL = "http://www.nber.org/papers/w5435",
 abstract = {Volunteer activity is work performed without monetary recompense. This paper shows that volunteering is a sizeable economic activity in the U.S.; that volunteers have high skills and opportunity costs of time; that standard labor supply explanations of volunteering account for only a minor part of volunteer behavior; and that many volunteer only when requested to do so.  This suggests that volunteering is a 'conscience good or activity' -- something that people feel morally obligated to do when asked, but which they would just as soon let someone else do.},
}