Julien Martin

Temperament, risk assessment and habituation to novelty in eastern chipmunks, Tamias striatus

An increasing number of studies are focusing on the role of animal temperament in the ecology of wild populations. One important step in these studies is to estimate the repeatability of temperament traits, by replicating measures of an animals behavioural or physiological reactions to a novel or stressful situation. When studies are performed in the field, several factors can affect repeatability estimates: (1) microenvironmental conditions prior to or during a test may affect the measured behaviour, and spatial heterogeneity in predation risk within the habitat of a population may affect repeatability; (2) a decrease over time in the strength of behavioural reactions as a result of habituation may bias repeatability; and (3) individuals may differ in their habituation. In this study we used a linear mixed-model approach to test for the occurrence of interindividual variation in behavioural reaction and habituation of eastern chipmunks, Tamias striatus, to a hole-board test and a handling bag test. We found high intraindividual consistency for the behaviours recorded both in the hole-board and handling bag tests; four temperament traits could be considered (i.e. activity/exploration, reaction to stress, emotionality and docility). Given that we found no phenotypic variation in habituation, chipmunks seem to show a behavioural carryover in activity/exploration and docility, which could have consequences for the evolutionary potential of habituation to novelty.

International Trade Price Indices

Export and import price indices are useful instruments in international economics. We document here TradePrices, our database of aggregated and sectoral trade price indices for all countries, computed using unit values given by BACI, the CEPII’s database of international trade at the product-level covering the period 1995-2004. Its rich country dimension allow an international comparison of prices evolutions. We compute “common” Laspeyres and Paasche indices but also “superlative” Fisher and Tornqvist indices, in both chained and fixed-base forms (chained Laspeyres and Paasche are also provided in their geometric form). In a first part, we discuss the characteristics of these different aggregation methods. In particular, we highlight the links between statistical methods and economical assumptions about implicit elasticity of substitution between goods. In a second step we describe the data. An exhaustive sensitivity analysis is done in order to determine the appropriate way to deal with technical difficulties, such as the treatment of measurement errors in bilateral unit values. Finally, this paper provides some stylized facts illustrating the necessity to provide a trade price database allowing international comparison and the usefulness of both aggregated and sectoral trade price indices to study international economics. TradeP rices database and SAS programs are freely available online, offering to users the possibility to choose the most accurate index for each particular purpose.

Knocking on Tax Haven's Door: Multinational Firms and Transfer Pricing

This paper analyzes the transfer pricing of multinational firms. Intrafirm prices may systematically deviate from arm’s-length prices for two motives: pricing to market and tax avoidance. Using French firm-level data on arm’s-length and intrafirm export prices, we find that the sensitivity of intrafirm prices to foreign taxes is reinforced once we control for pricing-to-market determinants. Most important, we find no evidence of tax avoidance if we disregard tax haven destinations. Tax avoidance through transfer pricing is economically sizable. The bulk of this loss is driven by the exports of 450 firms to ten tax havens.