A comment on "Network formation and efficiency in linear-quadratic games: An experimental study"
We replicate Horváth (2025), experimentally studying link formation and effort in a linear-quadratic game with positive externalities. Across five treatments, subjects exert 38–97 percent more effort than the Nash benchmark yet create too few links, depressing payoffs. In groups of five, the complete network appears in roughly 25 percent of final rounds (66–76 percent if deviations of ±2 links are allowed); in groups of nine it is almost never reached. Larger groups and lower link costs fail to improve connectivity. Following the original procedures and analysis step-for-step, our replication reproduces the sign, magnitude, and statistical significance of every reported effect. Robustness checks—learning, benefit salience, group benchmarking, alternative clustering, and multiple link-formation specifications—confirm the core pattern: persistent over-provision of effort coupled with under-provision of links, generating substantial efficiency losses.
JEL-Klassifikation: D85, D62, C92