The empirical analysis of media platforms economics has often neglected the multi-homing behaviour of advertisers. Assuming away the cross-substitutability and/or complementarity between the advertising slots of different platforms could damage the quality and the robustness of counterfactual analysis. To evaluate the consequence of such an abstraction, we compare the simulation results of hypothetical platform mergers when the demand on the advertising side is derived from a Translog cost model which allows for multi-homing, and when it is approximated by using a simple log-linear inverse demand model that ignores the differentiation among media platforms’ advertising slots. Ignoring the existence of substitutes or complements on the advertising side would result in overpredicting the losses of the viewers’ surplus and in underpredicting the gains in platforms’ revenues.

媒体平台经济学的实证分析往往忽略了广告商的多宿主行为。假设不同平台的广告位之间的交叉替代性和/或互补性可能会损害反事实分析的质量和稳健性。为了评估这种抽象的后果，我们比较了假设平台合并的模拟结果，当广告方面的需求来自允许多宿主的 Translog 成本模型时，当它使用简单的对数来近似时，忽略媒体平台广告位差异的线性逆需求模型。