Multi-Touch Media Attribution

Multi-touch media attribution distributes credit for a conversion across the sequence of marketing touchpoints a customer encountered, replacing crude heuristics like 'last click gets everything' with models that respect the whole journey. Two principled approaches dominate: graph-based Markov-chain models, advanced by Eva Anderl and colleagues, which represent customer paths as transitions between channels and value a channel by its 'removal effect' on the probability of conversion; and Shapley-value attribution, analyzed by Ron Berman, which treats channels as players in a cooperative game and assigns each its average marginal contribution across all possible coalitions. Both reject single-touch rules because those rules systematically misvalue channels — Berman shows that last-touch over-incentivizes the final exposure and can lower advertiser profit, while Anderl et al. demonstrate that Markov models recover credit allocations markedly different from simple heuristics. The result is a defensible, data-driven map of which channels actually move customers toward conversion, used to reallocate budget and compute channel-level return on ad spend. Because attribution is fundamentally about the incremental effect of exposures, it sits at the boundary of measurement and causal inference.