On the Additivity and Weak Baselines for Search Result Diversification Research

A recent study on the topic of additivity addresses the task of search result diversification and concludes that while weaker baselines are almost always significantly improved by the evaluated diversification methods, for stronger baselines, just the opposite happens, i.e., no significant improvement can be observed. Due to the importance of the issue in shaping future research directions and evaluation strategies in search results diversification, in this work, we first aim to reproduce the findings reported in the previous study, and then investigate its possible limitations. Our extensive experiments first reveal that under the same experimental setting with that previous study, we can reach similar results. Next, we hypothesize that for stronger baselines, tuning the parameters of some methods (i.e., the trade-off parameter between the relevance and diversity of the results in this particular scenario) should be done in a more fine-grained manner. With trade-off parameters that are specifically determined for each baseline run, we show that the percentage of significant improvements even over the strong baselines can be doubled. As a further issue, we discuss the possible impact of using the same strong baseline retrieval function for the diversity computations of the methods. Our takeaway message is that in the case of a strong baseline, it is more crucial to tune the parameters of the diversification methods to be evaluated; but once this is done, additivity is achievable

EU Accession Effects on the Demand for Manufactures: the Case of Greece

This paper analyzes the demand for manufactures in Greece and estimates the effects from the EU accession. An error correction specification of the Almost Ideal Demand System has been used. This formulation performs well on theoretical grounds, as the restrictions that are imposed by the demand theory are supported by the data provided. The results indicate that the domestic sales of manufactures are substitutes with imports from the EU and the rest of the world. Using the residuals approach, it is found that after the EU accession, imports from both sources substituted for a large part of the domestic sales.Elasticities, Error correction Almost Ideal Demand System, EU accession,

Benefits of travel time savings for freight transportation : beyond the costs

The purpose of this presentation is to investigate whether current practices in Cost Benefit Analysis do not underestimate the actual benefits accruing to the economy when transport investment reduces transport time. In a first section we define the different time related attributes of transport. We differentiate the various time dimensions of freight transportation services (time, reliability, frequency, responsiveness, etc). We decide to focus our analysis on Travel Time savings. We also investigate the meaning of the expression value of time in the specific context of freight transportation. We also recognise the variability of time perception among freight operators and between circumstances. In a second section we investigate the current practices in various European countries. We find that the overwhelming majority of countries estimate the benefits of improved network through the reduction in transport costs. However there is a strong case that the total benefits may exceed this mere cost reduction. In a third section, we show that shippers exhibit a significant willingness to pay for faster deliveries. This may have different causes like potential reorganisation of the production and distribution process, trading time consuming production technique against transport time, or increasing the time dimension of goods and services. This question should be carefully distinguished from the recurrent question about indirect effects. If direct effects are those that are captured by the supplier and consumer surplus of the market under study, then the potential extra benefit that are scrutinised in the study are part of the direct and not indirect effects. We also demonstrate that a benefit analysis based on traditional definitions of surplus should take into account these additional effects. We try to identify methods to measure these extra benefits. We review results obtained by previous attempts to measure this willingness to pay, based on RP data and SP exercises. We present the benefits and drawbacks of different measurement methods. Eventually, we show the impact of taking into account these extra benefits on projects' evaluation. and test the sensibility of Cost Benefit Ratio on a set of typical road investment projects in the U.K.

Externalities, Border Trade and Illegal Production: An Optimal Tax Approach to Alcohol Policy

This paper deals with optimal income and commodity taxation in an economy, where alcohol is an externality-generating consumption good. In our model, alcohol can be bought domestically, imported (via border trade) or produced illegally. Border trade implies an incentive to set the domestic alcohol tax below the marginal social damage of alcohol, and to tax (subsidize) commodities which are complementary with (substitutable for) alcohol. In addition, since leisure and alcohol consumption are generally nonseparable, the income tax will also be used as a corrective instrument. On the other hand, the desire to reduce the illegal production may generally affect the optimal income and commodity taxes in either direction. One possible (and arguably realistic) outcome is, nevertheless, that the desire to avoid the illegal production works to reduce both the alcohol tax and the marginal income tax rate.taxation; external effects; alcohol; border trade.

Gross domestic product: December 2013 quarter

New Zealand\u27s gross domestic product was up 0.9 percent in the December 2013 quarter, following a revised 1.2 percent rise in the September quarter. Key facts Gross domestic product (GDP): Economic activity increased 0.9 percent in the December 2013 quarter. Manufacturing (up 2.1 percent) and wholesale trade (up 3.2 percent) were the main drivers this quarter. Business services (down 2.1 percent) and agriculture, forestry, and fishing (down 2.0 percent) partly offset the growth. Economic activity for the year ended December 2013 was up 2.7 percent. Expenditure on gross domestic product: The expenditure measure of GDP was up 0.6 percent in the December 2013 quarter. Household consumption expenditure (up 1.3 percent) and exports (up 3.1 percent) were the main drivers of this rise. Inventories were run down by $18 million, due to manufacturing inventories being run down. Investment was up by 0.4 percent, driven by an increase in plant, machinery, and equipment. For the year ended December 2013, expenditure on GDP was up 2.5 percent

Cobb-Douglas Utility - Eventually!

Consider the following two opinions, both of which can be found in the literature of consumer demand systems: (a) As the real income of a consumer becomes indefinitely large, re-mixing the consumption bundle becomes irrelevant: having chosen the ultimately satisfying budget shares at any given set of relative prices, the superlatively wealthy continue to allocate additional income in the same proportions. With very large and increasing per capita income, ultimately the utility function becomes indistinguishable from Cobb-Douglas. (b) Consumer demand systems in which the income elasticities monotonically approach one (from above, in the case of luxuries; from below, in the case of necessities) are unsatisfactory both theoretically and empirically. For instance, a necessity with a low (consumer demand system; applied general equilibrium; separability; implicitly directly additive preferences; effectively global regularity; Cobb-Douglas, calibration; AIDADS.

The Demand For Wet Fish in Great Britain

Conventional empirical demand systems normally take prices to be exogenous, and determine the quantities demanded. Although this is logical for the individual consumer, at the market level the aggregate quantity traded may be exogenously determined, while the price vector changes to ensure the markets clear. It is suggested that this alternative scenario is particularly attractive for foodstuffs, and especially for wet fish, the commodity under consideration. An empirical analysis of the demand for wet fish in the UK using both the direct and indirect Translog models suggest that in this market, quantities are determining prices rather than the other way round. Furthermore, the two models provide widely different estimates of consumer preferences. This would suggest that more attention should be paid to the direction of causality in markets when undertaking formal demand analysis.inverse demand systems, wet fish, causality, Demand and Price Analysis, Environmental Economics and Policy, Resource /Energy Economics and Policy,

The QALY model and individual preferences for health states and health profiles over time: A systematic review of the literature

The numbers of quality-adjusted life years (QALYs) gained are increasingly being used to represent the gains in individual utility from treatment. This requires that the value of a health improvement to an individual is a simple product of gains in quality of life and length of life. The paper reports on a systematic review of the literature on two issues: whether the value of a state is affected by how long the state lasts; and by states that come before or after it. It was found that individual preferences over health are influenced by the duration of health states and their sequence. However, whilst there is much variation across individual respondents, the assumptions tend to hold much better when valuations are aggregated across respondents, which is encouraging for economic evaluations that rely on using average (mean or median) values

Implicit Additive Preferences: A Further Generalization of the CES

The CES is generalized by extension of the work of Hanoch (1975) resulting in implicit, direct and indirect relationships between utility and consumption. Expressions for substitution and income elasticities are developed and observed to be variable, rather than constant as in the CES case.Constant elasticity of substitution, implicit functions, preferences, demand

Introducing the indirect addilog system in a computable general equilibrium model: a case study for Palestine

A popular functional form for modeling the consumption block of a computable general equilibrium model (CGE) is the Linear Expenditure System (LES) for which the Engel curves are straight lines. To allow for more general shapes two other systems have been proposed in recent literature: An Implicitly Directly Additive Demand System (AIDADS, a generalization of LES) and the Specialized Constant Differences of Elasticities (CDE) system. To calibrate the parameters outside information on all income elasticities and all own price elasticities is needed, whereas LES only requires information on income elasticities and the Frisch parameter. In this paper we consider a special case of CDE, the Indirect Addilog System (IAS) that allows for non-straight Engel curves, whereas its outside data requirement is the same as for LES. The only disadvantage is that all cross price elasticities of a particular price are the same. In many developing countries there is hardly any information on price responses so that the AIDADS and CDE cannot be used. We propose the use of IAS rather than LES. In the empirical part we use IAS in a CGE model for Palestine and show that predictions of macro-economic indicators are remarkably close to those of IMF.Palestine;CGE model;indirect addilog system;consumption block;functional forms