We quantify competition among traders by the Herfindahl Index. The index is widely used to assess market concentration and it is computed as the sum of the squared market shares. We study the market for liquidity provision. In an electronic limit order book, liquidity is provided by passive orders and a trader’s market share is the fraction of passive limit order volume that this trader provide...

The Laakso–Taagepera index (Laakso and Taagepera, 1979) has become the most commonly used measure to specify the ‘effective’ number of political parties in a party system where parties vary substantially in their vote and/or seat shares. It is well known that the Laakso–Taagepera index is the inverse of the even more widely used Herfindahl–Hirschman index of concentration (Hirschman, 1945; Herf...

OBJECTIVE Physician antipsychotic prescribing behavior may be influenced by comparative effectiveness evidence, regulatory warnings, and formulary and other restrictions on these drugs. This study measured changes in the degree to which physicians are able to customize treatment choices and changes in physician preferences for specific agents after these events. METHODS The study used 2002-20...

Many risk, inequality, poverty and concentration measures are extremely sensitive to outliers, dependence, heterogeneity and heavy tails. In this paper we focus on robust measurement of risk, inequality, poverty and concentration under heterogeneity, dependence and heavy-tailedness of largely unknown form using the recent results on t−statistic based heterogeneity and correlation robust inferen...

extended abstract introduction hospitals are the most important and complex social units which are intended to protect the lives of people and to treat and improve them. with the passage of time and progress in science, hospitals have been equipped with more advanced technology and facilities. more active beds in hospitals are indications of specialized manpower, equipment and facilities for th...

BACKGROUND AND OBJECTIVE The efficiency and function of the pharmaceutical sector, as a vital portion of the health system, have a significant effect on intermediate and final indices of health. In this research, the structure of the pharmaceutical market in Iran was examined through the calculation of concentration indices in 2011. METHODS In this cross-sectional study, the needed data was g...

Concentration phenomena concern the ICT market. Though the regulatory action has been active mainly in the telecom network operators industry, even more significant worldwide concentration phenomena affect other industries. The market of mobile operating systems is analysed through two concentration indices to get a quantitative picture of the current situation and its evolution over time: the ...

In the recent years, resource depletion of inshore and coastal fisheries has seriously impacted Taiwan. Local fishing communities’ economic profits in these fisheries have declined and resulted in lower earned incomes for the fishermen. These phenomena have lead many scholars, government agencies and fishing communities to evaluate the optimal number of operating vessels in these fisheries. Thi...

Table B1 presents results from a specification identical to the one presented in Table 2 of the paper using an alternative measure of the concentration of power. This measure is the number of times the family that has held the paramount chieftaincy most has done so (i.e., the maximum of the number of times any family has held the chieftaincy). The mean of this variable is 3.5. The results are v...