The design of social welfare policies is often faced with a trade-off between the aim of not rejecting deserving claimants and the aim of not accepting undeserving claimants. To illustrate, social assistance schemes are intended to ensure that everyone has enough money to cover their basic subsistence costs. However, the government often lacks relevant information about whether or not a person satisfies the requirements for receiving such benefits. This creates the potential for making two types of errors: i. that some people receive benefits they are not entitled to, what we could call type 1 errors, and ii. that some people do not receive benefits they are entitled to, what we could call type 2 errors. We aim to study how people make this tradeoff using both opinion surveys and economic experiments and by doing so we add a new dimension to the study of prosocial preferences. In the survey study, we will present subjects with a vignette where the subjects are asked to assess the relative unfairness of type 1 and type 2 errors in the context of specific welfare policies. In particular, we are interested in describing the heterogeneity in how people make the trade-off between type 1 and type 2 errors. Additionally we aim to examine how these differences in trade-off relate to the support for social welfare policies, and to political preferences. In addition to describing the heterogeneity in how people make trade-offs between type 1 and type 2 errors in welfare policies within countries, we also aim to examine how this heterogeneity relates to attitudes towards welfare policy in countries with different welfare policies. In particular, we will use the survey study to compare attitudes to type 1 and type 2 errors in European countries with generous welfare schemes, such as the Scandinavian countries, to attitudes in countries with less generous welfare schemes, such as the US. The hypothesis we aim to test is that people in the first group of countries are more concerned with type 2 errors than type 1 errors, while the reverse is true for the latter group of countries. We will also conduct economic experiments where participants are faced with a trade-off between type 1 and type 2 errors in real incentivized economic situations. The basic idea behind the design is to have participants decide whether or not to transfer money from people who have earned money by doing a real effort task to participants who have not earned money. The key element of the design is that there is uncertainty concerning the reason why some participants did not earn money: either they did the same work as the participants who earned money (and are thus deserving) or they decided not to participate in the experiment (and are thus undeserving). Our focus is on how the decision to transfer money depends on the probability that the receivers are deserving.