Prediction markets are online trading platforms where contracts on future events are traded
with payoffs being exclusively linked to event occurrence. Scientific research has shown that
market prices of such contracts imply high forecasting accuracy through effective information
aggregation of dispersed knowledge. This phenomenon is related to incentives for truthful
aggregation in the form of real-money or play-money rewards. The question whether real- or
play-money incentives enhance higher relative forecast accuracy has been addressed by previous
works with diverse findings. The current state of empirical research in his field is subject to
two inherent deficiencies. First inter-market studies suffer from market disparities and
differences in the definition of underlying events. Comparisons between two different platforms
(one for play-money contracts one for real-money contracts) are potentially biased by
different trading behaviour. Second the majority of studies are based upon identical datasets
of market platforms (IOWA stock exchange Tradesports Intrade NewsFutures).
