Cognitive biases are an integral part of human conduct. However, we know little about how such biases affect street‐level bureaucrats' decision‐making. Without such an understanding, we might not have a complete picture about how street‐level bureaucrats make decisions. This incomplete picture can lead to the faulty implementation of public policy. This study focuses on cognitive biases that can impact decision‐makers faced with multiple claims. Using real‐world rulings made over 15 years by lower court judges in civil tax disputes, the findings reveal a positive association between the making of multiple claims by citizens in disputes with the state and the deciders' tendency to rule in their favor, especially when the ruling can be appealed. The findings also imply that the presentation of multiple claims can better the citizens' odds of receiving a favorable ruling. Policymakers who want to avoid such outcomes should take this factor into consideration.