The Role of Coordination Bias in Platform Competition

This paper considers platform competition in a two‐sided market that includes buyers and sellers. One of the platforms benefits from a favorable coordination bias in the market, in that for this platform it is less costly than for the other platform to convince customers that the two sides will coordinate on joining it. We find that the degree of the coordination bias affects the platform's decision regarding the business model (i.e., whether to subsidize buyers or sellers), the access fees, and the size of the platform. A slight increase in the coordination bias may induce the advantaged platform to switch from subsidizing sellers to subsidizing buyers, or induce the disadvantaged platform to switch from subsidizing buyers to subsidizing sellers. Moreover, in such a case the advantaged platform switches from oversupplying to undersupplying sellers, and the disadvantaged platform switches from undersupplying to oversupplying sellers.     

Monitoring the cross-covariances of a multivariate time series

In this paper sequential procedures are proposed for jointly monitoring all elements of the covariance matrix at lag 0 of a multivariate time series. All control charts are based on exponential smoothing. As a measure of the distance between the target values and the actual values the Mahalanobis distance is used. It is distinguished between residual control schemes and modified control schemes. Several properties of these charts are proved assuming the target process to be a stationary Gaussian process. Within an extensive Monte Carlo study all procedures are compared with each other. As a measure of the performance of a control chart the average run length is used. An empirical example about Eastern European stock markets illustrates how the autocovariance and the cross-covariance structure of financial assets can be monitored by these methods.     

Stochastic ordering and schur-convex functions in comparison of linear experiments

The usual ordering of linear experiments is defined by quadratic risk of attainable linear estimators. It is shown that under normality assumption this ordering can be introduced in a risk-free way by stochastic ordering of the estimators. Moreover an application of Schur-convex functions to design of experiments is presented. Partly supported by CPBP 0.1.02.     

Model uncertainty and efficiency measurement in stochastic frontier analysis with generalized errors

Journal of Productivity Analysis - Advanced efficiency measurement methods usually fall within Stochastic Frontier Analysis (SFA), Data Envelopment Analysis (DEA), or their derivatives. Although...     

The assessment of significance of benefits gained from the improvement of quality management systems in Polish organizations

The implementation and improvement of quality management systems conducted according to ISO 9001:2008 standards should bring benefits to any organization. On the basis of research conducted in 753 Polish companies, this publication presents results of analysis concerning the assessment of importance of benefits being a consequence of quality management system. The studies concerning the significance of benefits being a consequence of quality management systems in Polish companies allow claiming that financial benefits and markets ones are the most important for the management team whereas the organizational benefits are of less importance. It leads to neglecting ‘soft’ factors of quality management which are significant in TQM concept and drawing to much attention to so called hard factors- especially financial ones.     

Analysis of a network structure of the foreign currency exchange market

We analyse structure of the world foreign currency exchange (FX) market viewed as a network of interacting currencies. We analyse daily time series of FX data for a set of 63 currencies, including gold, silver and platinum. We group together all the exchange rates with a common base currency and study each group separately. By applying the methods of filtered correlation matrix we identify clusters of closely related currencies. The clusters are formed typically according to the economical and geographical factors. We also study topology of weighted minimal spanning trees for different network representations (i.e., for different base currencies) and find that in a majority of representations the network has a hierarchical scale-free structure. In addition, we analyse the temporal evolution of the network and detect that its structure is not stable over time. A medium-term trend can be identified which affects the USD node by decreasing its centrality. Our analysis shows also an increasing role of euro in the world’s currency market.     

Top-<Emphasis Type="Italic">k</Emphasis>-lists

Top-k-lists are introduced as sequences of k-dimensional random vectors with ordered components being k largest observations from a sequence of independent identically distributed random variables. Such lists changing in time are natural stochastic models of ranking tables which appear in many situations in real life, when one wants to keep a track of several best results in a given field. Here we study basic properties of top-k-lists as joint distributions, conditional structures, representations, driving examples of top-k-lists from exponential and uniform distributions, asymptotics and a relation to generalized order statistics.     

Amplification of shocks at the zero lower bound in a small open and large closed economy

This letter compares the consequences of hitting the zero lower bound in small open and large closed economies. I show that in a large economy shocks are modified by the zero lower bound on interest rate much more than in a small one – as a result, the large economy may suffer more.     

On characterizing discrete distributions via conditional expectations of weak record values

Let (W _n ,n ≥ 0) denote the sequence of weak records from a distribution with support S = { α₀,α₁,...,α _N }. In this paper, we consider regression functions of the form ψ _n (x) = E(h(W _n ) |W _n+1 = x), where h(·) is some strictly increasing function. We show that a single function ψ _n (·) determines F uniquely up to F(α₀). Then we derive an inversion formula which enables us to obtain F from knowledge of ψ _n (·), ψ _n-1(·), h(·) and F(α₀).