Competition in Turkish mobile telecommunications markets: Price elasticities and network substitution

This paper estimates demand elasticities for Turkish mobile telecommunications markets. In contrast to most other studies, firm-level data is used to estimate dynamic panel data models including instrumental variable techniques. Both short- and long-run elasticities are calculated, yielding a long-run price elasticity of −0.72 for the post-paid market and of −0.33 for the pre-paid market. The short-run price elasticity is estimated to be −0.36 for the post-paid market and −0.20 for the pre-paid market. In addition, there is evidence of fixed-to-mobile traffic substitution for consumers who use pre-paid cards.     

The Formation of GM‐free and GM Coasean Clubs: Will They Form and If So How Much Can They Achieve?

The unintended presence of traces of genetically modified (GM) crops in the harvests of non‐GM crops plays a prominent role in the debate over the coexistence of GM and non‐GM crops. One way to address the issue is the formation of GM‐free or GM‐only clubs. We model the decisions of individual farmers to cultivate either GM or non‐GM crops and combine this with a game theoretic model of club formation to investigate the feasibility of such clubs. We consider two liability regimes: GM farmers are liable or they are not. We consider two benchmarks: Nash equilibrium without negotiations and the efficient allocation and compare those with partial co‐operation through a Coasean club. We find that in both regimes a relatively large club can form but they are not always necessary to reach the efficient allocation. In fact, if farmers can freely decide under profit maximisation what to cultivate, they reach 95% of an efficient allocation. This holds independent of the property rights system and provides strong support for coexistence policies based on ex‐post liability such as in the US and Spain.     

Consumer choice and local network effects in mobile telecommunications in Turkey

The aim of this paper is to analyze the extent of network effects in mobile telecommunications in Turkey, and to identify other determinants of consumer choice based on consumer survey data. This study shows that there are regional disparities in the adoption of network services in Turkey, the attractiveness of the different networks varies for consumers between different regions. The results show that local network effects are significant for consumer choice. This finding means that consumers are more likely to be affected by the choices of other people within their local area than by the overall size of a network. Furthermore, local network effects also outweigh macro network effects at least in Turkey.     

Specification and Estimation of Production Functions Involving Damage Control Inputs: A Two-Stage, Semiparametric Approach

Productivity assessment of damage control inputs (such as pesticides) is complicated because their effect depends on the exposure to damage agents (such as pests). We discuss some open specification and estimation issues. The contribution is threefold. First, we elaborate the separability conditions for the damage control function and production function. Second, we employ a two-stage semiparametric technique to combine attractive features of both nonparametric and parametric approaches. Third, we model the interaction between pest exposure and damage control inputs by using slope dummies. An application to productivity analysis of small scale Bt cotton production in China illustrates the approach.     

Mobile number portability in Europe

This paper examines the causes and effects of mobile number portability (MNP) and provides a survey of its implementation in Europe. It first examines the competitive effects and costs of introducing MNP. Next, it discusses how to charge for MNP. It argues that a price cap regime starting from the average cost of porting is likely to provide appropriate incentives. Finally, it reviews recent experience with implementing MNP in Europe. Differences in the speed of porting and porting charges appear to explain part of the differences in the use of MNP across countries.     

Vertical Unbundling in the EU Electricity Sector

In its September 2007 package of energy policy proposals the European Commission has expressed a clear preference for ownership unbundling as the most effective way of separating transmission from other stages of the value chain, which is regarded as necessary in order to promote infrastructure investment, fair network access and market transparency. The welfare effects of this measure are, however, still hotly debated. The following articles highlight the pros and cons of ownership unbundling. * Thanks are due to Alberto Prandini for earlier discussions on this topic and to Hieu Tran for excellent research assistance. Funding from the UK Economic and Social Research Council is gratefully acknowledged. ** The contribution of this author is on personal title and does not bind the NMa in one way or another.