Some properties of the minimum and the maximum of random variables with joint logconcave distributions

It is shown that if (X ₁, X ₂, . . . , X _n ) is a random vector with a logconcave (logconvex) joint reliability function, then X _P = min _i∈P X _i has increasing (decreasing) hazard rate. Analogously, it is shown that if (X ₁, X ₂, . . . , X _n ) has a logconcave (logconvex) joint distribution function, then X ^P  = max _i∈P X _i has decreasing (increasing) reversed hazard rate. If the random vector is absolutely continuous with a logconcave density function, then it has a logconcave reliability and distribution functions and hence we obtain a result given by Hu and Li (Metrika 65:325–330, 2007). It is also shown that if (X ₁, X ₂, . . . , X _n ) has an exchangeable logconcave density function then both X _P and X ^P have increasing likelihood ratio.     

The Impact of Frictions in Routine Execution on Economies of Scope

Research summary: Based on a detailed database of a beverages producer‐distributor that expanded its product variety by leveraging its logistic network, we show that product diversification generates economies of scope and also higher operational costs. The result is an inverted‐U relationship between variety and productivity: When the firm offers few additional categories, productivity grows, but as the number of categories rises, the costs of executing the operational routines increase rapidly and productivity falls. The negative effect on productivity increases if the added product category is more dissimilar to previous ones, and decreases with learning from operational experience. Our results highlight how frictions at the operational level can limit the benefits of diversification, even in the absence of other sources of diseconomies, such as increased coordination needs. Managerial summary: One of the prevalent reasons for companies to expand to adjacent product lines is attaining economies of scope. However, such growth strategy also generates operational frictions, even if the day‐to‐day routines do not appear to change at all. Product diversity is disruptive for routine execution, as it requires coordination and exception handling, and may ultimately overcome any efficiency obtained from growth. We estimate the relevance of such operational friction using data from a beverages distribution network. When product variety is low, additional categories do generate efficiency, but after reaching a given threshold, friction prevails. We find that operational friction increases when products are more dissimilar, but is attenuated when workers learn from their own and other's experience. Copyright © 2017 John Wiley & Sons, Ltd.     

Employment shifts, economic reform and the changes in public/private sector wages in Mexico: 1987–1997

Over the last decade, the public sector in Mexico experienced substantial fiscal reform, divestiture of public enterprises, and the elimination of many regulations affecting pay and employment. This study analyzes the changes in the public/private sector differences in wages during the 1987–1997 period. The results from analyzing microdata from the Encuesta Nacional de Empleo Urbano show that relative public sector wages increased from 1987 to 1997. Most of the relative wage increase in the public sector can be explained by increases in the price of skills and by changes in sorting across sectors. The results have important public policy implications since they suggest that public sector workers earn more and their wages have grown faster than those of their private sector counterparts. As such, policies contemplating public sector reform should take into account the effect of these measures on the inter-sectoral income distribution and the overall economic growth. First version received: April 2000/Final version received: December 2000     

LABOR INCOME DIFFERENTIALS WITHIN THE LATIN AMERICAN FREE TRADE AREA (LAFTA)

This article considers the major results of a study of relative wage structures in the LAFTA region. It first discusses the nature and methodology of the study, which was undertaken for ECIEL. Data on the size of labor income differences are introduced, and an attempt is made to determine the causes of such differences, and to relate them to various wage differentials. The main findings of the study are then summarized, with discussions of inter-country, intra-country, and occupational labor income differentials and their causes. Finally, the results of the study are updated to the end of 1970, and some conclusions are derived regarding the inter-temporal behavior of wages in LAFTA.     

Inequality and criminality revisited: further evidence from Brazil

The objective of this study is to shed light on the determinants of criminality rates in Brazil. A panel data model was estimated using Brazilian states’ data. Our main result suggests that income inequality plays an important role in the determination of the crime rate. Furthermore, there are evidence suggesting that both unemployment and urbanization rates are positively related to crime. Based on a GMM approach we find the existence of an “inertial effect” on criminality. Besides that, the GMM results show that public security spending is effective in reducing criminality rates. Contrary to the common wisdom, we could not find evidence that poverty increases violent crimes. Finally, we have evidence that income inequality Granger causes crime, but not the reverse.     

A serial supply chain of newsvendor problem with safety stocks under complete and partial information sharing

We consider a supply chain where multiple members are serially connected. The decision is to determine the ordering quantity of a member to the next upstream member in the supply chain. The basic cost model is similar to the newsvendor problem with additional consideration to safety stock. This paper presents optimal approaches for coordination of the supply chain under both complete and partial information sharing in order to maximize the total expected benefit. For complete information sharing we develop an optimal coordination algorithm. For partial information sharing, we propose an optimal coordination algorithm based on the Alternating Direction Method and the Diagonal Quadratic Approximation Method. A numerical example is discussed to show the optimal convergence of ordering quantities and discuss the properties of the proposed algorithms.     

Regulation of international roaming in the European Union—Lessons learned

This paper analyzes the evolution of prices and competition in intra-EU international roaming markets. It addresses three main research questions: (i) to what extent have market forces by themselves brought competition to retail roaming markets? (ii) Has the evolution of market dynamics in wholesale roaming improved competition? (iii) Is wholesale regulation sufficient to lead to a reduction in retail roaming prices? Data show that there has been little price-based competition both at wholesale and retail levels, despite prices being well above costs and the significant margins allowed by regulation. Available data from the period preceding the entry into force of the first EU roaming regulation also point to the same conclusion. Lack of competitive pressure in retail roaming markets and inelastic demand give little incentives for retail roaming service providers to lower prices. Wholesale international roaming markets have complex competition dynamics. They are characterized by the reciprocity of wholesale roaming agreements and traffic internalization inside transnational groups. These circumstances limit price competition at the wholesale level. The traditional regulatory approach applied to electronic communication markets has been primarily focused on wholesale regulation. However, empirical evidence shows that even if wholesale charges are reduced, retail roaming markets continue to operate at very high retail margins (for example, more than 200% retail mark-up over wholesale charges for data roaming services and incoming calls). This proves that in international roaming markets wholesale charge reductions are not necessarily passed on to retail prices. It can thus be inferred that wholesale price regulation alone is in most cases not sufficient to ensure that benefits are passed through to end users.     

Strategy and structure redux

Forty years on from Alfred Chandler's seminal book Strategy and Structure , in the following pages contemporary strategists examine the book's impact and Chandler's contribution to business theory.     

Currency diversification and export competitiveness: A model of the ‘Dutch disease’ in Egypt

The paper presents a dynamic portfolio model under currency inconvertibility which rationalizes the recent Egyptian experience of real exchange rate appreciation and currency diversification following the increase in oil exports and the partial financial liberalization that took place after 1976. The two shocks are linked because the relative price of manufacturing exports in terms of oil is also the premium of the ‘gray’ market rate over the official exchange rate. The effects of various official exchange rate policies on the temporary equilibrium values of the premium and the real wage and on the steady-state values of asset stocks are examined. A review of the Egyptian experience in light of the model results suggests that the unification of 1979 was ineffective against this variant of the ‘Dutch disease’ but that the restoration in 1981 of a parallel rate closer to the ‘gray’ market rate applicable to competitive exports may be more effective.