The article by Armin Falk and James J. Heckman discusses the role of laboratory experiments in advancing causal knowledge in the social sciences. While laboratory experiments have been widely used in the physical and life sciences, their adoption in the social sciences has been slower, particularly in psychology. The authors address common objections to lab experiments, such as the lack of "realism" and generalizability, and argue that these concerns are often based on misunderstandings of the nature of scientific evidence and the data collected in labs. The article highlights the advantages of lab experiments, including controlled variation, which allows for precise testing of theories and behavioral assumptions. Lab experiments can provide reliable and "real" data by controlling decision environments, material payoffs, and information available to participants. This controlled setting enables the isolation of causal effects, which is crucial for understanding complex social phenomena. The authors also discuss the complementarity between lab and field experiments. Field experiments can provide insights into more realistic settings, while lab experiments offer controlled conditions that are essential for testing specific theories and assumptions. They argue that the choice between lab and field experiments depends on the research question and the specific conditions being studied. Both methods are valuable and should be used in conjunction to enhance the understanding of social behaviors and institutions. Finally, the article addresses other objections to lab experiments, such as the representativeness of student subjects, small sample sizes, and potential biases from Hawthorne effects. The authors suggest that these issues can be mitigated through careful design and analysis, and that lab experiments can still produce valuable and informative results. In conclusion, the authors emphasize that controlled variation is essential for causal knowledge in the social sciences, and that both lab and field experiments have their unique strengths and should be used in combination to advance empirical research.The article by Armin Falk and James J. Heckman discusses the role of laboratory experiments in advancing causal knowledge in the social sciences. While laboratory experiments have been widely used in the physical and life sciences, their adoption in the social sciences has been slower, particularly in psychology. The authors address common objections to lab experiments, such as the lack of "realism" and generalizability, and argue that these concerns are often based on misunderstandings of the nature of scientific evidence and the data collected in labs. The article highlights the advantages of lab experiments, including controlled variation, which allows for precise testing of theories and behavioral assumptions. Lab experiments can provide reliable and "real" data by controlling decision environments, material payoffs, and information available to participants. This controlled setting enables the isolation of causal effects, which is crucial for understanding complex social phenomena. The authors also discuss the complementarity between lab and field experiments. Field experiments can provide insights into more realistic settings, while lab experiments offer controlled conditions that are essential for testing specific theories and assumptions. They argue that the choice between lab and field experiments depends on the research question and the specific conditions being studied. Both methods are valuable and should be used in conjunction to enhance the understanding of social behaviors and institutions. Finally, the article addresses other objections to lab experiments, such as the representativeness of student subjects, small sample sizes, and potential biases from Hawthorne effects. The authors suggest that these issues can be mitigated through careful design and analysis, and that lab experiments can still produce valuable and informative results. In conclusion, the authors emphasize that controlled variation is essential for causal knowledge in the social sciences, and that both lab and field experiments have their unique strengths and should be used in combination to advance empirical research.