Too Popular, Too Fast: Optimal Advertising and Entry Timing in Markets with Peer Influence

We study optimal advertising and entry timing decisions for a new product being sold in two-segment markets in which followers are positively influenced by elites, whereas elites are either unaffected or repulsed by product popularity among followers. Key decisions in such markets are not only how much to advertise in each segment over time but also when to enter the follower segment. We develop a continuous-time optimal control model to examine these issues. Analysis yields two sets of two-point boundary value problems where one set has an unknown boundary value condition that satisfies an algebraic equation. A fast solution methodology is proposed. Two main insights emerge. First, the optimal advertising strategy can be U-shaped, that is, decreasing at first to free-ride peer influence but increasing later on to thwart the repulsion influence of overpopularity causing disadoption. Second, in markets where cross-segment repulsion triggers disadoption, advertising is only moderately effective, and entry costs are high, managing both advertising and entry timing can result in significantly higher profits than managing only one of these levers. In markets without disadoption, with high advertising effectiveness or with low entry costs, in contrast, delaying entry may add little value if one already manages advertising optimally. This implies that purveyors of prestige or cool products need not deny followers access to their products in order to protect their profits, and can use advertising to speed up the democratization of consumption profitably. This paper was accepted by Juanjuan Zhang, marketing.

An Empirical Dynamic Model of Trade with Consumer Accumulation

This paper develops a dynamic structural model of trade in which firms slowly accumulate consumers in foreign markets. Estimating the model using export data from individual firms and a particle Markov chain Monte Carlo estimator, the model predicts lower survival rates for new exporters and estimates low entry costs of exporting—less than half of those estimated in the absence of consumer accumulation. Using simulations and out-of-sample predictions, I show that the introduction of such frictions and the reduction in estimated entry costs allow the model to match important facts regarding the aggregate response of international trade to shocks. (JEL D22, F12, F14, L66)

Technology entry in the presence of patent thickets

We analyse how patent thickets affect entry into patenting. A model of entry into patenting that allows for variation in technological opportunity, technological complexity and the extent of patent thickets is developed and analysed. Using UK data we then show that patent thickets are associated with a reduction of first time patenting in a technology controlling for the level of technological complexity and opportunity. Technologies characterized by more technological complexity and opportunity attract more entry into patenting. Our evidence indicates that patent thickets raise entry costs, which leads to less entry into technologies regardless of a firm’s size.

Entry Costs, Task Variety, and Skill Flexibility: A Simple Theory of (Top) Income Skewness

This paper develops a simple model that provides a unified explanation for both an increase in below-top skewness and a much larger increase in within-top skewness of wage income distribution. It relies on a single mechanism based on the fixed costs of firm entry. A decrease in entry costs increases the variety of goods/tasks and thus the demand for higher-skilled workers who are more flexible in handling a variety of tasks, which increases both types of skewness. Differences in flexibility are modeled as differences in the fixed labor setup costs required to handle a given number of tasks. Our numerical experiments in a calibrated model show that a decrease in entry costs – entry deregulation – can be a quantitatively important source of both the increase in below-top skewness and the much larger increase in within-top skewness observed in the U.S. Moreover, the experiments imply that the observed differences in entry deregulation can cause significant differences in the top skewness across countries that have similar technological change. This can provide an answer to Piketty and Saez’s (2006) question: Why have top wages surged in English speaking countries in recent decades but not in continental Europe or Japan, which have gone through similar technological change?