Wie gut sind die Prognosen der Arbeitsgemeinschaft wirtschaftswissenschaftlicher Forschungsinstitute in der Bundesrepublik Deutschland?:- Ein Kommentar

Ohne Zusammenfassung     

Comment Did PATCO really lead to the British miners’ strike?*

Here Herbert Northrup Duncan Campbell discuss an article published in this Journal (Vol 17 No 2 Summer 1986)-the author subsequently responds to their comments.     

The average number of events per time unit and its estimation

Let ζ _t be the number of events which will be observed in the time interval [0;t] and define as the average number of events per time unit if this limit exists. In the case of i.i.d. waiting-times between the events,E[ζ _t ] is the renewal function and it follows from well-known results of renewal theory thatA exists and is equal to 1/τ, if τ>0 is the expectation of the waiting-times. This holds true also when τ = ∞.A may be estimate by ζ _t /t or where is the mean of the firstn waiting-timesX ₁,X ₂, ...,X _n . Both estimators converage with probability 1 to 1/τ if theX _i are i.i.d.; but the expectation of may be infinite for alln and also if it is finite, is in general a positively biased estimator ofA. For a stationary renewal process, ζ _t /t is unbiased for eacht; if theX _i are i.i.d. with densityf(x), then ζ _t /t has this property only iff(x) is of the exponential type and only for this type the numbers of events in consecutive time intervals [0,t], [t, 2t], ... are i.i.d. random variables for arbitraryt > 0.     

Structure and Dynamics of Livestock Marketing in Rural Uganda: Constraints and Prospects for Research and Development

ABSTRACT

The projected global expansion in consumption of meat and other livestock products potentially offers sub-Saharan African small-holder farmers opportunities to escape from the poverty trap. A necessary condition for exploiting this potential is the establishment of marketing systems that provide farmers with reasonable incentives to participate in the market. In this study, the functioning of livestock markets in rural Uganda is analyzed based on a survey of 401 livestock keepers, complimented with focus group discussions with livestock traders and policy planners. The first part is dedicated to the empirical analysis of key organizational and institutional arrangements. Constraints along the marketing chain as well as potential institutional solutions are illuminated. The second part is dedicated to propositions of new areas where more work and new results are needed to improve the functioning of the livestock marketing chain. Empirical findings indicated the following institutional constraints: a poor market information system, lack of grades and standards, lack of trade finance, poor contract enforcement and dispute settlement, disorganized actors, high transaction risks, and poorly developed marketing infrastructure. The study recommends a structured approach to livestock marketing, market infrastructure development, and emphasis on arbitration systems as specific ways of improving the efficiency of livestock marketing in Uganda and other developing countries.