  Modern decision making tools are based on statistical analysis of abundant
data, which is often collected by querying multiple individuals. We consider
data collection through crowdsourcing, where independent and self-interested
agents, non-experts, report measurements, such as sensor readings, opinions,
such as product reviews, or answers to human intelligence tasks. Since the
accuracy of information is positively correlated with the effort invested in
obtaining it, self-interested agents tend to report low-quality data.
Therefore, there is a need for incentives that cover the cost of effort, while
discouraging random reports. We propose a novel incentive mechanism called Peer
Truth Serum that encourages truthful and accurate reporting, showing that it is
the unique mechanism to satisfy a combination of desirable properties.
