Economic determinants of global mobile telephony growth

This study examines the substitution effect between fixed-line and mobile telephony while controlling for the consumption externality associated with telephone networks. A dynamic demand model is estimated using a global telecommunications panel dataset comprised of 56 countries from 1995–2000. Estimation results show the presence of a substantial substitution effect. Additionally income and own-price elasticities are reported. Analysis of impulse responses for price, income and network size indicate substantial mobile telephone growth is yet to be realised. However, price ceilings imposed in the fixed-line network can retard the growth of the mobile network.     

The complementarity between calls and messages in mobile telephony

This article estimates price elasticities of demand for mobile telephone calls and messages. We use panel data consisting of telephone bills to Portuguese mobile telephony consumers. In order to account for the unobserved individual heterogeneity and data censoring, we estimate a Tobit model for panel data with individual random effects. The demands for calls and messages are inelastic. Calls and messages are found to be complements.     

Diffusion of mobile telephony in India: An empirical study

Diffusion of new technology is an important driver of economic growth. In this paper, diffusion of mobile telephony in India is studied. There is a vast diffusion potential in this country which needs to be exploited efficiently and in a rational way. This paper investigates the social, technological, economical and political (STEP) factors that have influenced the diffusion process of mobile telephony especially the diffusion speed. The epidemic model, which is widely employed in the diffusion studies of mobile telephony, is used for the study. The data is fitted into logistic, gompertz, and bass models by nonlinear least squares and it is found that gompertz model best describes the diffusion process of mobile telephony in India. The study reveals that competition and government intervention played a significant role in accelerating the diffusion speed of mobile telephony by making the technology affordable. It is found that mobile telephony is a substitute for fixed line telephony in India. The findings will be useful in taking managerial decisions with respect to factors in forecasting and controlling the diffusion process of emerging technologies.     

Leapfrogging in mobile telephony: A measure for comparing country performance

There is widespread agreement as to what constitutes leapfrogging in technology and also that mobile phones are a good example of this phenomenon. What is lacking in the literature, however, is any attempt to operationalize the notion of leapfrogging in a way that allows us to rank different countries. The purpose of this paper accordingly is to provide such a measure using both the ratio of mobile to fixed telephones and a weighting of this ratio for a particular country by its share in the total number of mobile phones in the sample. The proposed measure yields a number of insights that cannot be gained by using only the ratio of mobile to fixed telephones. Yet, for a number of the best performing countries this ratio is very much in evidence.     

Service quality in Brazilian mobile telephony: an efficiency frontier analysis

The mobile telephony sector is characterized by the dynamic interplay of rapid changes in technology and an apparently growing competition, as indicated by the fierce nonprice competition, and is yet associated with the entry of new operating companies in some cases. In this context, a relevant and neglected issue is the assessment of how service quality responded to an increasingly competitive environment. This study utilizes data envelopment analysis to assess the quality efficiency of mobile telephony companies in Brazil during the 2000–2003 period. Window analysis was conducted for the entire period, taking as reference different quality indicators pertaining to different forms of complaints and calls completed and interrupted. The efficiency measurement was made feasible by interpreting the indicators reflecting a positive dimension of quality as outputs and those reflecting negative aspects of quality as inputs. Given potential heterogeneities across firms that relate to the frequency band and to the technology (time division multiple access technology and code division multiple access technology among others), this article considered adjusted efficiency scores. The Tobit model for censored data was estimated to control for the aforementioned aspects. Rescaled residuals from the econometric estimation produced efficiency scores for service quality. The evidence indicated an overall improvement in efficiency over time. Nonparametric tests were consistent with a positive evolution of quality over time even for shorter subperiods.     

The diffusion of mobile telephony in Italy and the UK: an empirical investigation

Since its appearance mobile telephony has shown a remarkably fast diffusion pattern in most advanced countries. This paper investigates technological and economic factors that have influenced the diffusion process of cellular phones, in particular the diffusion speed and the upper limit. The epidemic model widely used in diffusion studies is summarised and discussed highlighting the evolutionary disequilibrium nature of diffusion processes. Moreover, the econometric specification of some of the models distinguishes between long-run relationships and short-run adjustments to a continuously evolving pattern. We find that the new digital technology, which coincides with increased competition in both Italy and the UK, has made the process faster and increased the saturation level in Italy, but not in the UK; in Italy only the decreasing price of the handset has affected the diffusion process, whereas we find that, in addition to that, decreasing tariffs and increasing consumption expenditures have been significant in shaping the diffusion process of mobile telephony in the UK.     

Estimating demand function parameters of mobile applications

The vibrant market for mobile applications has raised awareness of several professional and also voluntary software developers. The key question especially for professional developers is how to improve the profit gained with a developed app. Recent research provided evidence on the factors that determine the demand of a mobile app. This paper presents a procedure to estimate demand function parameters that are required for developing pricing, advertising and also product update strategies. More specifically, the procedure estimates an app’s maximal willingness to pay, demand elasticity on price and network value. The procedure is based on the Fulfilled Expectations Cournot Model and requires knowledge about the apps being considered as substitutes to each other. It is applied to a data set consisting of download rank data of Apple iPhone apps.     

Estimating local average treatment effects in aggregate data

In some contexts, the effect of a treatment can be estimated with easily accessible aggregate rather than individual data, using difference-in-difference estimation. However, under imperfect assignment within groups, this produces intent-to-treat estimates, which may not be the treatment effect of interest. This article provides a method for estimating local average treatment effects using aggregate data. I also suggest a data source that allows the method to be applied when treatment rates are not recorded.     

Estimating the variance of decomposition effects

We derive the asymptotic variance of the Blinder–Oaxaca decomposition effects. We show that the delta method approach that builds on the assumption of fixed regressors understates true variability of the decomposition effects when regressors are stochastic. Our proposed variance estimator takes randomness of regressors into consideration. Our approach is applicable to both the linear and nonlinear decompositions. Previously, only a bootstrap method has been a valid option for nonlinear decompositions. As our derivation follows the general framework of m-estimation, it is straightforward to extend our variance estimator to a cluster-robust variance estimator. We demonstrate the finite-sample performance of our variance estimator with a Monte Carlo study and present a real-data application.     

Fixed-to-mobile call substitution and telephony market definition in Korea

An appropriate market definition is critical in most antitrust cases. In practice, antitrust authorities define economic markets in a deterministic manner with little concern about the risk involved in defining markets incorrectly. In contrast, this article proposes a probabilistic market definition method by which antitrust authorities can establish a statistical confidence level for their intended market-definition judgments. As an application, we examine the likelihood that the fixed-line and mobile telephony services in Korea can compete in the same economic market. Combining critical loss analysis with a hierarchical Bayes model for stated preference data, we find some evidence for the separation of the fixed-line and mobile telephony markets in present-day Korea. After discussing certain possible regulation biases for market definition, we predict that the two markets will converge in the near future as the mobile price premium continues to decrease.     

Estimating the effects of forward guidance in rational expectations models

Simulations of forward guidance in rational expectations models should be assessed using the “modest policy interventions” framework introduced by Eric Leeper and Tao Zha. That is, the estimated effects of a policy intervention should be considered reliable only if that intervention is unlikely to trigger a revision in private sector beliefs about the way that monetary policy will be conducted. I show how to constrain simulations of forward guidance to ensure that they are regarded as modest policy interventions and illustrate the technique using a medium-scale DSGE model estimated on US data. I find that many experiments that generate the large responses of macroeconomic variables deemed implausible by many economists – the so-called “forward guidance puzzle” – are not modest policy interventions. Those experiments should therefore be treated with caution, since they may prompt agents to believe that there has been a change in the monetary policy regime that is not accounted for within the model. More reliable results can be obtained by constraining the experiment to be a modest policy intervention. In the cases I study, the quantitative effects on macroeconomic variables are more plausible when this constraint is imposed.     

Upstream regulation in mature network industry: evidence from Nordic mobile telecommunications markets

This article investigates the effects of upstream regulation that aims to create niches and attract new type of entrants on the competitive environment of downstream markets. Using unique cross-country data of Nordic mobile telecommunications markets, we show that upstream regulation leads to (i) increases in both number and aggregate market share of service-based providers in the downstream market, (ii) an increase in the number of service-based providers, thus increasing their aggregate market share, but no opposite direction of results and (iii) a lower retail price level, proxied by average revenue per user. Our findings imply that upstream regulation may be able to achieve better outcomes when the policy objectives are to revitalize mature network industries and to enhance consumer welfare.     

Estimating the effects of coordinated fiscal actions in the euro area

We estimate spillover effects of a fiscal shock in one member country in the euro area on outputs of the rest of the members, using a global vector autoregression (GVAR) model. We compare the effects of a domestic fiscal shock with those of a similar size area-wide shock expressed as a weighted average of the fiscal shocks across all member countries. According to our estimates, the impact of an area-wide fiscal shock on output of a member country tends to be positive and larger than that of a domestic shock. Since the cost of participating in the area-wide shock is lower than the cost of a similar size domestic shock, our finding indicates the importance of coordinated fiscal actions in the euro area.     

Estimating the employment effects of education for disabled workers in Norway

In this paper we evaluate the effectiveness of educational programmes used as an employment strategy for disabled workers in Norway. To obtain these estimates we follow the employment career of a sample of participants in educational programmes and nonparticipants three years after they had left the vocational rehabilitation benefit system. We specify an employment outcome model that includes both unobserved heterogeneity and selection bias due to correlation between unmeasured factors and a person's training status. Even though participants in educational programmes have employment rates that are around eight percentage points higher than those who did not participate in such programmes, econometric selection models produce a training effect for education not significantly different from zero. First version: Jan 2001/Final version received: April 2002  The data were provided by The Norwegian Social Data Service in Bergen. I would like to thank Dag Kiberg for preparing the raw data. All the data are gathered from sources at The Directorate of Labour, The Social Insurance Organization and Statistics Norway. None of the mentioned institutions are in any circumstances responsible for the analysis or for the conclusions drawn from it.     

Estimating three-dimensional nonlinear panel data models with interactive effects

This article considers two three-step estimation approaches to three-dimensional nonlinear panel data models with interactive effects correlated with the independent variables. We propose a Nonlinear Least Squares-Principal Component Analysis-Grid Search iterated approach to estimate the static model, and a GMM-PCA-GS iterated method to the dynamic model. Monte Carlo experiments examine the finite sample performance of the methods.     

Network effects and the choice of mobile phone operator

This paper explores the role of network effects in the consumer’s choice of mobile phone operators in the UK. It contributes to the existing literature by taking a new approach to testing for direct network effects and by using individual-level data, which allows to analyse the impact that the immediate social network has on consumer choice in network markets. For our empirical analysis we use two sources of data: market-level data from the British telecommunications regulator OFCOM and micro-level data on consumers’ usage of mobile telephones from the survey, Home OnLine. We estimate two classes of models which illustrate the role of network effects. The first is an aggregate model of the comparative volume of on-net and off-net calls. This finds that the proportion of off-net calls falls as mobile operators charge a premium for off-net calls, but even in the absence of any price differential between on-net and off-net, there is still a form of pure network effect, where a disproportionate number of calls are on-net. The second is a model of the individual consumer’s choice of operator. This finds that individual choice shows considerable inertia, as expected, but is heavily influenced by the choices of others in the same household. There is some evidence that individual choice of operator is influenced by the total number of subscribers for each operator, but a much stronger effect is the operator choice of other household members.     

Viewpoint: Estimating the causal effects of policies and programs

Estimation, inference and interpretation of the causal effects of programs and policies have all advanced dramatically over the past 25 years. We highlight three particularly important intellectual trends: an improved appreciation of the substantive importance of heterogeneous responses and of their methodological implications, a stronger focus on internal validity brought about by the “credibility revolution,” and the scientific value that follows from grounding estimation and interpretation in economic theory. We discuss a menu of commonly employed partial equilibrium approaches to the identification of causal effects, emphasizing that the researcher's central intellectual contribution always consists of making an explicit case for a specific causal interpretation given the relevant economic theory, the data, the institutional context and the economic question of interest. We also touch on the importance of general equilibrium effects and full cost–benefit analyses.     

Employment effects of the provision of specific professional skills and techniques in Germany

Based on unique administrative data, which has only recently become available, this paper estimates the employment effects of the most important type of public sector sponsored training in Germany, namely the provision of specific professional skills and techniques (SPST). Using the inflows into unemployment for the year 1993, the empirical analysis uses local linear matching based on the estimated propensity score to estimate the average treatment effect on the treated of SPST programs by elapsed duration of unemployment. The empirical results show a negative lock-in effect for the period right after the beginning of the program and significantly positive treatment effects on employment rates of about 10 percentage points and above a year after the beginning of the program. The general pattern of the estimated treatment effects is quite similar for the three time intervals of elapsed unemployment considered. The positive effects tend to persist almost completely until the end of our evaluation period. The positive effects are stronger in West Germany compared to East Germany.     

Free and second-best entry in oligopolies with network effects

We compare the number of firms in equilibrium in a Cournot industry with positive network effects and complete compatibility, under free and second-best entry. Under free entry, the firms decide whether to enter the market or not; in the second-best problem, the number of firms is established by the regulator to maximize social welfare (the regulator controls entry but not production). We show that when individual equilibrium output decreases with entry (business-stealing competition), free entry may lead to more or less firms than the second-best problem. This contrasts with the standard (nonnetwork) Cournot oligopoly model, wherein with business-stealing competition, free entry leads to an excessive number of firms compared with the second-best solution.     

Employment effects of payroll taxes - an empirical test for Germany

This study tests to what degree the incidence of payroll taxes in Germany is on employment and whether in consequence payroll taxes, in particular social insurance contributions, are the culprit behind the growing unemployment problem. Using industry level data for 18 years (1977–1994) a system of five dynamic factor demand equations is estimated. Various simulations indicate that the employment effects of payroll taxes are minimal.