Technology Timing and Pricing In the Presence of an Installed Base

This paper studies a vendor.s timing and pricing strategies to tackle its own installed base when selling a newly improved product. We characterize the market with either a partly- or fully- covered installed base, consumers. relative willingness to pay for the newly improved version of the product, and their relative payoffs from delayed purchase. Instead of using the conventional assumption of constant consumer reservation price, we propose that if consumers already own an existing (old) version of a durable product, their willingness to purchase the newly improved version would increase over time. This effect, interweaving with consumer heterogeneity on valuation of quality and purchase history, may enable perfect intertemporal price discrimination (Salant 1989). We find that upgrade pricing may not be able to differentiate consumers with different purchase history when consumer heterogeneity is sufficiently high. Instead, the vendor would maximize its profit through intertemporal price discrimination, delayed product introduction, or pooling pricing. By overcoming the intractability of studying delayed product introduction in a market with heterogeneous consumers, this study analytically confirms Fishman and Rob.s conjecture (2000) that heterogeneity in consumers. valuation of quality may discourage a vendor to launch a new product. Particularly, consumers. anticipation of future price reduction can lead to delayed product introduction even when the extent of quality improvement embodied in the new product is high.New product introduction, intertemporal price discrimination, delayed product introduction, installed base, upgrade policy

Partner Heterogeneity Increases the Set of Strict Nash Networks

Galeotti et al. (2006, [2]) show that all minimal networks can be strict Nash in two-way flow models with full parameter heterogeneity while only inward pointing stars and the empty network can be strict Nash in the homogeneous parameter model of Bala and Goyal (2000, [1]). In this note we show that the introduction of partner heterogeneity plays a major role in substantially increasing the set of strict Nash equilibria.

Modelling heterogeneity to estimate the ex ante value of biotechnology innovations

After more than a decade of GM crops, literature reports farmers and consumers can gain significantly from the technology, despite the intellectual property rights assigned to the innovator. In this paper we assess the effect of heterogeneity on this distribution of benefits. A two dimensional framework is created to assess the ex ante benefits of an innovation. Given this setting and the scarce data often available, a parametric modelling approach is taken. The two dimensions of heterogeneity, spatial and temporal, are explicitly modelled as they have a different importance for different technologies. Using this framework we can simulate different corporate pricing strategies and evaluate the benefits generated under changing heterogeneity. The framework is tested on the introduction of HT sugar beet in the EU-27.Heterogeneity, Parametric modelling, ex ante, Research and Development/Tech Change/Emerging Technologies,

Not All Trade Restrictions are Created Equally

There has been great focus in the recent trade theory literature on the introduction of firm heterogeneity into trade models. This introduction has highlighted the importance of the entry/exit decision of firms in response to changes in trade barriers. However, it is typical in many of these models to use iceberg transport costs as a general form of trade barriers that can be interchangeable with ad valorem tariffs. I show that this is not always an appropriate conclusion. Specifically, I illustrate that profit for an exporter is more elastic in response to tariffs than iceberg transport costs, which has implications for total product variety. One such implication is the possibility for there to be an anti-variety effect associated with lower transport costs while there also being a pro-variety effect associated with lower tariffs.Intra-industry Trade; Trade policy; Firm heterogeneity; Monopolistic competition

Modeling survival times using frailty models

Traditional survival models, including Kaplan Meier, Nelson Aalen and Cox regression assume a homogeneous population; however, these are inappropriate in the presence of heterogeneity. The introduction of frailty models four decades ago addressed this limitation. Fundamentally, frailty models apply the same principles of survival theory, however, they incorporate a multiplicative term in the distribution to address the impact of frailty and cater for any underlying unobserved heterogeneity. These frailty models will be used to relate survival durations for censored data to a number of pre-operative, operative and post-operative patient related variables to identify risks factors. The study is mainly focused on fitting shared and unshared frailty models to account for unobserved frailty within the data and simultaneously identify the risk factors that best predict the hazard of death.peer-reviewe

A Political Economy Theory of Government Debt and Social Security

This paper analyzes the determinants of government debt and social security for the old in a closed-economy, overlapping-generation model. Under the probabilistic voting, the model presents (i) an intergenerational link of resource allocation via debt and social security; (ii) multiple political equilibria; and (iii) a negative cor- relation between tax and debt. These three results are robust to the introduction of public goods as an alternative government expenditure or to the introduction of income heterogeneity within a generation.Government debt; Social security; Overlapping generations; Proba- bilistic voting

An ion probe study of the sulphur isotopic composition of Fe-Ni sulphides in CM carbonaceous chondrites

From the Introduction: The CM chondrites have endured variable degrees of aqueous alteration [1] which has changed their original mineralogy. A detailed study of the petrology and mineralogy of the sulphides in a suite of increasingly aqueously altered CMs, combined with sulphur isotope data measured in situ, can provide clues as to whether differences in the CM group are a result of different degrees of aqueous alteration, or whether they are the result of nebular heterogeneity

On the role of unobserved preference heterogeneity in discrete choice models of labour supply

The aim of this paper is to analyse the role of unobserved preference heterogeneity in structural discrete choice models of labour supply. Within this framework, unobserved heterogeneity has been estimated either parametrically or semiparametrically through random coefficient models. Nevertheless, the estimation of such models by means of standard, gradient-based methods is often difficult, in particular if the number of random parameters is high. For this reason, the role of unobserved taste variability in empirical studies is often constrained since only a small set of coefficients is assumed to be random. However, this simplification may affect the estimated labour supply elasticities and the subsequent policy recommendations. In this paper, we propose a new estimation method based on an EM algorithm that allows us to fully consider the effect of unobserved heterogeneity nonparametrically. Results show that labour supply elasticities and other post-estimation results change significantly only when unobserved heterogeneity is considered in a more flexible and comprehensive manner. Moreover, we analyse the behavioural effects of the introduction of a working-tax credit scheme in the Italian tax-benefit system and show that the magnitude of labour supply reactions and the post-reform income distribution can differ significantly depending on the specification of unobserved heterogeneity.behavioural microsimulation; labour supply; unobserved heterogeneity; random coefficient mixed models; EM algorithm

The noisy voter model on complex networks

We propose a new analytical method to study stochastic, binary-state models on complex networks. Moving beyond the usual mean-field theories, this alternative approach is based on the introduction of an annealed approximation for uncorrelated networks, allowing to deal with the network structure as parametric heterogeneity. As an illustration, we study the noisy voter model, a modification of the original voter model including random changes of state. The proposed method is able to unfold the dependence of the model not only on the mean degree (the mean-field prediction) but also on more complex averages over the degree distribution. In particular, we find that the degree heterogeneity ---variance of the underlying degree distribution--- has a strong influence on the location of the critical point of a noise-induced, finite-size transition occurring in the model, on the local ordering of the system, and on the functional form of its temporal correlations. Finally, we show how this latter point opens the possibility of inferring the degree heterogeneity of the underlying network by observing only the aggregate behavior of the system as a whole, an issue of interest for systems where only macroscopic, population level variables can be measured.Comment: 28 pages, 9 figure