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Michal Krawczyk, Ernesto Reuben

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This article reports results of a field experiment in which two hundred e-mails were sent to authors of recent articles in economics that had promised to send the interested reader supplementary material, such as alternative econometric specifications, "upon request." The e-mails were sent either by a researcher affiliated at Columbia University, New York or the University of Warsaw, Poland; furthermore, the authors' position (assistant professor) was specified in half the e-mails only. Overall, 64% of the approached authors responded to our message, of which two thirds (44% of the entire sample) delivered the requested materials. The frequency and speed of responding and delivering were very weakly affected by the position and affiliation of the sender. Gender of affiliation of the author, number of citations or journal impact factory or the type of object in question seemed to make no difference. However, authors of published articles were much more likely to share than authors of working papers.

Michal Krawczyk

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This study makes use of an unusual opportunity to manipulate framing of a simple decision under uncertainty: whether or not to answer an exam question when unsure which answer is correct and a missing response is scored higher than an incorrect one. Two treatments were compared in a natural field experiment: one in which the decision was framed in terms of losses, and the other - in terms of gains. Some alternative theories of decision making under risk, notably prospect theory, propose that individuals display reflection effect, i.e. tend to be more risk-seeking in losses than gains. No such evidence was found: subjects were generally risk-averse and this disposition was not affected by treatment.

Wojciech Hardy, Michal Krawczyk, Joanna Tyrowicz

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In this project, we investigate downloading and sharing behaviour in a novel 'piracy game' modelled after standard public good games. We find that willingness to share correlates positively with the sharing by others. By contrast, actual behaviour in the 'piracy game' is not correlated with self-reported behaviour.

Michal Krawczyk

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Several studies have identified the "better than average" effect - the tendency of most people to think they are better than most other people on most dimensions. The effect would have profound consequences (see e.g. Barber and Odean (2001)). These findings are predominantly based on non-incentivized, non-verifiable self-reports. The current study looks at the impact of incentives to judge one's abilities accurately in a framed field experiment. Nearly 400 students were asked to predict whether they would do better or worse than average in an exam. The most important findings are that subjects tend to show more confidence when incentivized and when asked before the exam rather than afterwards. The first effect shows particularly in females.

Michal Krawczyk, Joanna Rachubik

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The representativeness heuristic (RH) has been proposed to be at the root of several types of biases in judgment. In this project, we ask whether the RH is relevant in two kinds of choices in the context of gambling. Specifically, in a field experiment with naturalistic stimuli and a potentially extremely high monetary pay-out, we give each of our subjects a choice between a lottery ticket with a random-looking number sequence and a ticket with a patterned sequence; we subsequently offer them a small cash bonus if they switch to the other ticket. In the second task, we investigate the gambler's fallacy, asking subjects what they believe the outcome of a fourth coin toss after a sequence of three identical outcomes will be. We find that most subjects prefer "random" sequences, and that approximately half believe in dependence between subsequent coin tosses. There is no correlation, though, between the initial choice of the lottery ticket and the prediction of the coin toss. Nonetheless, subjects who have a strong preference for certain number combinations (i.e., subjects who are willing to forgo the cash bonus and remain with their initial choice) also tend to predict a specific outcome (in particular a reversal, corresponding to the gambler's fallacy) in the coin task.

Michal Krawczyk

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This paper reports a field experiment involving manipulation of invitations to register in an experimental economics subject database. Two types of invitations were sent out: one emphasizing pecuniary and the other non-pecuniary benefits of participation. The former resulted in higher response rate and the strength of this treatment effect was comparable in different groups defined by gender and academic major. In a follow-up test conducted about a year later it was found that individuals recruited by invitations emphasizing monetary benefits were less willing to make an effort to participate in a non-paid survey. The very same survey also showed that they were marginally less altruistic in general.

Michal Krawczyk

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This study is a field experiment on loss aversion. The framing of scoring rules was differentiated in two exams at the University of Warsaw, with only half the students facing explicit penalty points in the case of giving an incorrect answer. Loss aversion predicts that less risk will be taken (less questions will be answered) when losses are possible but in fact, no treatment effect was observed.

Wojciech Hardy, Michal Krawczyk, Joanna Tyrowicz

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We report results of an experimental study analyzing the effects of Internet piracy on book sales. We conducted a year-long controlled large-scale field experiment with pre-treatment pair matching. Half of the book titles received experiment treatment, in which a specialized agency would immediately remove any unauthorized copy appearing on the Internet. For the other half we merely registered such occurrences, but no countermeasures were taken. For all the titles we obtained print and e-book sales statistics from the publishers. We find that removal of unauthorized copies was an effective method of curbing piracy, but this had no bearing on legal sales.

Michal Krawczyk, Magdalena Smyk

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Bibliometric studies show that male academics are more productive than their female counterparts and that the gap cannot be explained in terms of difference in abilities. In this project we wish to verify the hypothesis that this tendency is related to the greater support that men receive from their colleagues ("old boys network"). Towards this end we had e-mails sent by a male or female student asking academics for a minor favour. In Study 1 we asked authors of nearly 300 papers in experimental economics to share the raw data used in their study. We observed no difference in response rate or compliance rate between male and female senders. In Study 2 we sent 2775 e-mails to academics affiliated with prestigious schools from ten different fields, asking to either send us a copy of their recent article of meet the sender supposedly interested in pursuing a PhD program. Once again we manipulated gender of the senders but this time we also varied their physical attractiveness. We found a small but significant difference in the Article Treatment: attractive females' requests were honoured less often. No such tendency was found in the Meeting Treatment and no general gender effect was observed. Overall, we find very little support for the claim that early-stage male researchers enjoy greater support than their female colleagues.

Anouar El Haji, Michal Krawczyk, Marta Sylwestrzak, Ewa Zawojska

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Auctions often require risk taking under time pressure. However, little is known about how time pressure moderates the relationship between uncertainty of outcomes and bidding behavior. This study consists of a field experiment in which participants are invited to a Vickrey auction to elicit their willingness to pay for a lottery ticket. The time available to place a bid and also the skewness of the lottery (holding the expected value constant) are systematically manipulated. We find that under high time pressure participants are less likely to place a bid at all. Furthermore, participants who do place a bid under high time pressure bid significantly less than participants under low time pressure. The main finding is thus that increased time pressure significantly decreases risk taking. The effect seems to be particularly strong for the lottery with a high probability of winning and for female subjects.

Michal Krawczyk, Joanna Rachubik

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Despite having the same probability of being drawn, certain number combinations are more popular than others among the lottery players. One explanation of such preferences is the representativeness heuristic (RH). Unlike previous hypothetical experiments, in the present experiment we used real-life lottery tickets, involving a high payout in case of winning to elicit true preferences. To verify if people prefer randomly-looking number combinations, participants were to choose a preferred ticket. To validate if it is likely to be caused by RH, we correlated preference for "random" sequences with the belief in dependence between subsequent coin tosses. We confirm that people strongly prefer random sequences and that a non-trivial fraction believes in dependence between coin tosses. However, there is no correlation between these two tendencies, questioning the RH explanation. By contrast, participants who have an (irrationally) strong preference for number combinations also tend to make (irrationally) specific predictions in the coin task. Unexpectedly, we find that females are considerably more likely to belong to this groups than males.