Platform self-preferencing is often attacked as being “unfair.” Proponents of the consumer welfare standard of antitrust complain that a fairness standard is too vague and too untethered from competitive effects to be useful. However, the consumer welfare standard relies on assessment of whether competition is on the “merits,” and the criteria for merits substantially overlap with those for fairness. I show that: (a) depending on the circumstances, self-preferencing can strengthen or weaken the intensity of competition among incumbents, and can make entry easier or more difficult; and (b) the common criteria for fairness and merit do not reliably identify the direction of these competitive effects. Instead, a case-by-case, fact-intensive analysis of actual competitive effects is needed.
