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Voluntary Contributions with Imperfect Information Annamaria Fiore University of Bari M. Vittoria Levati Andrea Morone MPI of Economics, Jena University of Bari University of Bari. Motivation.
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Voluntary Contributions with Imperfect Information Annamaria Fiore University of Bari M. Vittoria Levati Andrea Morone MPI of Economics, Jena University of Bari University of Bari ESA World Meeting 2007
Motivation • to examine the effect of incomplete information on contribution levels • two-person linear voluntary contribution mechanism with stochastic marginal benefits from the public good • most previous experimental studies performed in an extremely rich informational environment Yet,in real life, one hardly knows in advance the marginal benefit she can derive from a public good she is asked to finance ESA World Meeting 2007
Hipothesis • A severe lack of information may lower individuals’ willingness to contribute (Bagnoli and Lipman, 1989, “complete information […] is a very strong assumption […]. Incomplete information may lead to underprovision, p. 585) • to establish a relationship between attitude to risk and willingness to contribute (Ledyard, 1995, p. 143) ESA World Meeting 2007
Experiment • Two treatments: • PERFECT INFO • IMPERFECT INFO • Between design • 32 participants in each treatment • Computerized (Ztree, Fischbacher, 1999) • Subject pool: students in Economics – recruitment: ORSEE software (Greiner, 2004) • Lab at MPI, Jena, Germany, on February 2005 • 2 stages: • 1° stage: Vickrey auction • 2° stage: public goods game & belief elicitation • Currency: ECU (10 ECU = 1€) • Average payoff: 11.7€ per un’ora e mezzo ESA World Meeting 2007
Results (1/4) • The difference in contribution decisions between treatments is remarkable and significant (two-sided Wilcoxon rank-sum tests - based on averages over players for each pair as independent unit of observation – p<0.001 in each of the first nine periods; p=.92 in period 10; N = 16; p=.001; N = 16 averaging over all periods). ESA World Meeting 2007
Results (2/4) • 1° period: independent obs. • individual contributions and individual beliefs: highly significantly correlated (Spearman rank correlation coefficients are 0.83 in PERFECT INFO, and 0.80 in IMPERFECT INFO in each treatment) • a statistically significant difference in first-period beliefs between treatments (one-tailed Wilcoxon rank-sum test: p-value = .004, N = 32). No participant is expected to free-ride under perfect information, whereas 6 subjects hold free-riding expectations under imperfect information. ESA World Meeting 2007
Results (3/4) • beliefs in all periods following the first: endogenous • correlation analysis between beliefs in period t about the partner’s contribution in t and the actual contribution of the partner in period (Spearman rank correlation coefficients: PERFECT INFO = .92 IMPERFECT INFO = .98, p-value < .001, N = 16) ESA World Meeting 2007
Relationship risk attitude/willingness to contribute (4/4) ESA World Meeting 2007
Conclusion • Evidence for the impact of imperfect information on voluntary contribution behavior in linear public goods games, and for the relationship between risk attitudes and willingness to cooperate • Linear voluntary contribution mechanism: efficient? • Political economy perspective: individuals provided with a good knowledge about their marginal benefits if requested to contribute ESA World Meeting 2007
Thanks for your attention! Annamaria Fiore University of Bari afiore@dse.uniba.it ESA World Meeting 2007