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91.
92.
Guido Brunner 《Intereconomics》1978,13(11-12):263-266
Science and technology have come under the fire of critics over the last ten years or so, but the present situation of mankind will call for more, and not less, human ingenuity. A particular problem for Europe to master is the need to improve the channels for translating scientific achievements into competitive engineering and technology. It is a problem which can best be solved within a coherent policy framework, designed and implemented at Community level.  相似文献   
93.
Several state‐of‐the‐art binary classification techniques are experimentally evaluated in the context of expert automobile insurance claim fraud detection. The predictive power of logistic regression, C4.5 decision tree, k‐nearest neighbor, Bayesian learning multilayer perceptron neural network, least‐squares support vector machine, naive Bayes, and tree‐augmented naive Bayes classification is contrasted. For most of these algorithm types, we report on several operationalizations using alternative hyperparameter or design choices. We compare these in terms of mean percentage correctly classified (PCC) and mean area under the receiver operating characteristic (AUROC) curve using a stratified, blocked, ten‐fold cross‐validation experiment. We also contrast algorithm type performance visually by means of the convex hull of the receiver operating characteristic (ROC) curves associated with the alternative operationalizations per algorithm type. The study is based on a data set of 1,399 personal injury protection claims from 1993 accidents collected by the Automobile Insurers Bureau of Massachusetts. To stay as close to real‐life operating conditions as possible, we consider only predictors that are known relatively early in the life of a claim. Furthermore, based on the qualification of each available claim by both a verbal expert assessment of suspicion of fraud and a ten‐point‐scale expert suspicion score, we can compare classification for different target/class encoding schemes. Finally, we also investigate the added value of systematically collecting nonflag predictors for suspicion of fraud modeling purposes. From the observed results, we may state that: (1) independent of the target encoding scheme and the algorithm type, the inclusion of nonflag predictors allows us to significantly boost predictive performance; (2) for all the evaluated scenarios, the performance difference in terms of mean PCC and mean AUROC between many algorithm type operationalizations turns out to be rather small; visual comparison of the algorithm type ROC curve convex hulls also shows limited difference in performance over the range of operating conditions; (3) relatively simple and efficient techniques such as linear logistic regression and linear kernel least‐squares support vector machine classification show excellent overall predictive capabilities, and (smoothed) naive Bayes also performs well; and (4) the C4.5 decision tree operationalization results are rather disappointing; none of the tree operationalizations are capable of attaining mean AUROC performance in line with the best. Visual inspection of the evaluated scenarios reveals that the C4.5 algorithm type ROC curve convex hull is often dominated in large part by most of the other algorithm type hulls.  相似文献   
94.
The United Nations Development Program has published its Human Development Index values for most countries of the world for the past five years. It claims the index provides information that goes beyond the widely-used GDP data and is relevant for policy-making. Critical examination shows that the index does not yet live up to this claim.  相似文献   
95.
96.
In the monetary policy literature it is common to assume that trend inflation is zero, despite overwhelming evidence that zero inflation is neither empirically relevant nor a practical objective for central bank policy. We therefore extend the standard New Keynesian model to allow for positive trend inflation, showing that even low trend inflation has strong effects on optimal monetary policy and the dynamics of inflation, output and interest rates. Under discretion, the efficient policy deteriorates and there is no guarantee of determinacy. Even with commitment, targeting non-zero trend inflation leads to substantial welfare losses. Our results serve as a warning against indiscriminate use of models assuming zero trend inflation.  相似文献   
97.
98.
External shocks may cause a decline in the productivity of fixedcapital in certain regions of an economy. Exogenous obstaclesto migration make it hard for workers in those regions to reallocateto more prosperous regions. In addition, firms may devise "attachment"strategies to keep workers from moving out of a local labormarket. When workers are compensated in kind, they find it difficultto raise the cash needed for migration. This endogenous obstacleto migration has not yet been considered in the literature.The article shows that the feasibility of attachment dependson the inherited structure of local labor markets: attachmentcan exist in equilibrium only if the labor market is sufficientlyconcentrated. Attachment is beneficial for both employers andemployees but hurts the unemployed and the self-employed. Ananalysis of matched household-firm data from the Russian Federationcorroborates the theory.  相似文献   
99.
Unemployment, growth and taxation in industrial countries   总被引:14,自引:1,他引:13  
To the layman, the upward trend in European unemployment is related to the slowdown of economic growth. We argue that the layman's view is correct. The increase in European unemployment and the slowdown in economic growth are related, because they stem from a common cause: an excessively rapid growth in the cost of labour. In Europe, labour costs have gone up for many reasons, but one is particularly easy to identify: higher taxes on labour. If wages are set by strong and decentralized trade unions, an increase in labour taxes is shifted onto higher real wages. This has two effects. First, it reduces labour demand, and thus creates unemployment. Secondly, as firms substitute capital for labour, the marginal product of capital falls; over long periods of time, this in turn diminishes the incentive to invest and to grow. The data strongly support this view. According to our estimates, the observed rise of 14 percentage points in labour tax rates between 1965 and 1995 in the EU could account for a rise in EU unemployment of roughly 4 percentage points, a reduction of the investment share of output of about 3 percentage points, and a growth slowdown of about 0.4 percentage points a year.  相似文献   
100.
A Positive Theory of Social Security   总被引:8,自引:0,他引:8  
In many countries, social security accounts for a large fraction of the government budget. Why is this so, given that at any point in time the number of recipients of social security benefits is smaller than the number of contributors? In the overlapping‐generations model studied in this paper, all individuals currently alive vote on social security in every period. In equilibrium, the size of social security is larger, the greater is the proportion of elderly people in the population, and the greater is the inequality of pre‐tax income within each generation. Both predictions of the theory are supported by the empirical evidence in cross‐country data.  相似文献   
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