Papers Under Review and Working Papers

Saman Modiri, Scott Fay, The Role of Delivery Performance in Shaping Customer Satisfaction in Multi-Marketplace Platforms: Evidence from Brazilian E-Commerce (Available upon request)

This paper examines how delivery performance shapes customer satisfaction in multi-marketplace platforms (MMPs), where a single store owner lists products across multiple online marketplaces and manages logistics on behalf of small and midsize business (SMB) sellers. Using transaction-level data from Olist, a Brazilian MMP, we exploit the fact that last-mile delivery is controlled by third-party carriers, not sellers, to causally identify the effect of late delivery on a rich set of customer outcomes. Beyond star ratings, we construct sentiment, emotion, topic attribution, and review quality measures using transformer-based NLP models. We find that late delivery substantially reduces review scores, sentiment, and review quality while increasing frustration, with negative effects persisting after time, location and seller fixed effects. Critically, topic decomposition reveals that delivery-induced dissatisfaction spills over to perceptions of product quality and seller reputation imposing a reputational externality on sellers who had no role in the logistics failure. Heterogeneity analysis using causal forests shows that customers given shorter delivery promises are more forgiving of delays, while longer delivery estimates amplify the marginal penalty. These findings carry implications for how marketplace platforms design delivery promises, how store owners manage logistics quality, and how SMB sellers navigate a reputational environment they partially control.

Saman Modiri, Scott Fay, Not So Fast! How Delivery Time Impacts a Multi-Channel Retailer’s Profit

Employing a stylized analytical model, we study how the delivery time for online orders affects the profitability of a multi-channel retailer that operates both an online channel and physical stores. In this paper, we ask whether faster delivery always increases a retailer's profit. Interestingly, we find that it can be profitable for a retailer to delay delivery even if faster delivery were costless and logistically feasible. In particular, a “Delayed Delivery” strategy is optimal when (a) consumers’ travel costs to the physical store are small, (b) consumers differ substantially in their valuations for the product, and (c) high-value consumers experience greater disutility from shopping online than do low-value consumers. Furthermore, we find that delaying delivery can induce a retailer to serve more consumers, introduce an online channel (when there otherwise would be only physical stores), and/or fully segment the market. Counterintuitively, we show that Delayed Delivery can create a win-win scenario in which both the firm and consumers benefit from online orders being delivered less promptly. Lastly, delaying delivery can be equally profitable to offering a menu of shipping options in which a premium is charged for faster delivery.

Saman Modiri, Liangbin Yang, Amiya Basu, A Multi-Metric Approach to TV Advertising Effectiveness (Available upon request)

While prior research highlights variation in consumer response to TV advertising, most established measures operate at the aggregate level and overlook individual-level variation. Moreover, studies often examine ad effectiveness through isolated metrics, limiting a holistic understanding of advertising impact. This paper addresses both gaps by proposing a multi-metric framework that captures heterogeneous responses to TV ads across three key purchase behaviors: transaction rate, retention likelihood, and average spending. Using a combination of two established stochastic models and a robust empirical framework, we estimate how consumers respond to advertising across these dimensions. Our findings reveal that advertising negatively affects average transaction rates but positively influences average retention likelihood, with no significant effect on average spending. Further analysis across consumer quantiles uncovers additional heterogeneity: advertising improves retention among loyal customers but may induce opportunistic behavior or forward-buying in the broader market, leading to reduced transaction rates for some segments. These results underscore the complex nature of advertising effects and the importance of analyzing them through multiple lenses.