Working Paper: CEPR ID: DP17779
Authors: Francesco Decarolis; Muxin Li; Filippo Paternollo
Abstract: This paper offers the first systematic quantitative assessment of default-option interventions designed to mitigate Google's search dominance. By analyzing interventions in the European Economic Area, Russia, and Turkey, we find that, across all three cases, changes to default settings effectively reduced Google's market share. The causal impact amounts to less than 1 percentage point in the EEA and over 10 percentage points in Russia and Turkey. Differences arise from intervention nuances, including the size of the targeted users' group, local market characteristics, and remedy designs. We discuss the complexity of assessing the interventions' impact on welfare deriving from quality responses.
Keywords: online advertising; antitrust; platform competition
JEL Codes: C45; D44; G34; L13; L81; M37
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Interventions in the European Economic Area (EEA) (O52) | Reduction of less than 2 percentage points in Google's market share (D49) |
| Interventions in Russia (F51) | Reduction of approximately 7 percentage points in Google's market share (F61) |
| Interventions in Turkey (F51) | Reduction of about 12 percentage points in Google's market share (D49) |
| Regulatory interventions (G18) | Changes in market share in treatment countries compared to control countries (C22) |
| Local market characteristics and intervention designs (D40) | Variation in the effectiveness of interventions (I24) |