Successful Scientific Replication and Extension of Levitt (2008): Child Seats are Still No Safer Than Seat Belts

Using US fatality data from 1975 to 2003, Levitt (Evidence that seat belts are as effective as child safety seats in preventing death for children aged two and up, Review of Economics and Statistics 2008; 90 (1): 158–163) shows that child safety seats do not significantly reduce fatalities for children aged 2–6 years as compared to standard seat belts. Although we were unable to gain access to the original programs and dataset used, we were able to replicate Levitt's ( 2008 ) findings almost exactly. We extend Levitt ( 2008 ) by showing that the findings also hold for the years 2004–2011 despite changing driver characteristics and restraint use patterns. We fail to find evidence that SUVs provide additional safety for children. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparaison de la rentabilité des systèmes conventionnels et biologiques en production laitière au Québec

De la banque de données AGRITEL, 336 fermes conventionnelles et 16 fermes biologiques, spécialisées en production laitière, sont sélectionnées. Sept groupes (dont un est biologique) sont alors formés correspondant à des concepts de production différents. Les groupes defermes conventionnelles correspondent à des niveaux d'intrants particulièment élevés (haut niveau d'intrants) ou faibles (bas niveau d'intrants), ainsi qu'à des niveaux de production élevés @roduction intensive) oufaibles (production extensive), pour le troupeau ou pour l'ensemble de l'entreprise.
Les fermes biologiques parviennent à des résultats technico-économiques et financiers au moins aussi bons que les fermes avec des rendements élevés (intensifs). En revanche, même si les concepts de production sont proches, les différences de rendement et de rentabilité sont assez nettes (souvent signcatives) entre le groupe biologique et les groupes extensifs ou à bas niveau d'intrants. Les entreprises biologiques sont plus équilibrtés et la prédominance de la production laitière est moindre. Les coûts de main-d'œuvre sont toutefois plus élevés que la plupart des groupes d'entreprises conventionnelles.
Cette étuaè nous laisse croire qu'il est possible d'amtéliorer la rentabilité des fermes extensives et à bas niveau d'intrants, dont les concepts de production se rapprochent de ceux de l'agriculture biologique.     

Union Co‐operation in a Context of Job Insecurity: Negotiated Outcomes from Teamworking

This paper explores the ‘mutual gains’ argument that employees benefit when teamworking is introduced alongside employee involvement in problem‐solving and within a co‐operative industrial relations climate. It reports worker outcomes from negotiations to introduce teamworking across two steelworks. Moderate union branches and employees at one of the works (Scunthorpe) co‐operated with managers in joint problem‐solving teams to redesign work. However, contrary to mutual gains expectations, greater job insecurity at this works coerced union branches to accept teamworking agreements containing extensive demanning and a pay increase for fewer employees. Employees perceived greater job security at the other works (Teesside) and by rejecting joint problem‐solving with managers, militant union branches protected more jobs and extracted higher payment for teamworking. The findings indicate that job insecurity can lead co‐operative unions down a slippery slope of coerced co‐operation restricting employee benefits from teamworking.     

Demand and cost impacts of the 2 mm technology program in the US motor-vehicle market

We assess the impact on demand and producers’ costs of a new technology implemented in the US auto industry, the 2 mm program. This is a fascinating case partially because of the unique collaboration among public agencies and a consortium of manufacturers and universities. Using a type of hedonic price model for demand, we show that the new technology was responsible for a short-lived increase in demand for vehicles produced by US automakers at increased producers’ costs. Firms that refused to participate in the consortium attained smaller net gains implementing the technology independently. Overall, our approach differs from that of previous analysts in that we (1) separate demand from supply, (2) employ a comprehensive vehicle database, spanning 1981–1998 data, including data on virtually all vehicle models sold in the USA, as well as data on plants’ and producers’ technology characteristics, and (3) rely on sales and production data rather than plant data. Also, we quantify the cost of not participating in the consortium.     

Time inconsistency as a rationale for public unemployment insurance

A role for public unemployment insurance is developed based on the inability of the government to commit to a future rate of unemployment. This is illustrated using a model in which a minimum wage policy combined with unemployment insurance is welfare-improving. Unemployment insurance could be decentralized to the private sector if the government could commit to a minimum wage. However, if not, a government that acts in the interest of the workers will have an incentive to increase the minimum wage to exploit private insurers. In the absence of commitment, an equilibrium with private unemployment insurance will not exist.     

Wage–vacancy contracts and multiplicity of equilibria in a directed search model of the labour market

This paper studies a directed search model of the labour market, which is standard in all aspects except two. First, we allow firms to post wage–vacancy contracts advertising the number of workers they would pay as well as the payment all will receive. Second, we consider two cases: one where workers are risk neutral and one where workers are risk averse, both in finite and large economies. Our paper shows that when firms post wage–vacancy contracts, whether workers are modelled as risk neutral or risk averse matters: the types of symmetric equilibria and the nature of multiplicity of equilibria are different. Somewhat surprisingly, when there are finite numbers of risk‐neutral workers and firms, we obtain a finite number of symmetric equilibria, but when workers are risk averse, we obtain a continuum of equilibria. Furthermore, our paper sounds a cautionary note on using large economies as an approximation of finite economies: when workers are risk neutral, the nature of equilibrium is preserved going from a finite to a large economy, but the nature of equilibrium is different when workers are risk averse.     

Measuring the social value of local public goods: an empirical analysis within Paris metropolitan area

A non-linear hedonic model is used to estimate the implicit marginal prices of 17 local public goods in a Paris suburban area on an original data set of some 8200 housing units. The results reveal a robust effect of local public school quality (measured both by the fraction of junior high school students that are at least two years behind grade level and the student/teacher ratio) on house prices. It is observed that housing owners’ marginal willingness to pay for reducing commuting time is roughly similar for public transportation than for car transportation. Another noticeable result is the complete capitalization of local taxes at a discount rate of 3.5%. An illustration of the potential usefulness of the results for Cost–Benefit analysis is also provided.     

Credibility of propensity score matching estimates. An example from Fair Trade certification of coffee producers

Propensity score matching (PSM) is an increasingly popular method for evaluation studies in agricultural and development economics. However, statisticians and econometricians have stressed that results rely on untestable assumptions, and therefore, guidelines for researchers on how to improve credibility have been developed. We follow one of these guidelines with a data set analysed by other authors to evaluate the impact of Fair Trade certification on the income of coffee producers. We provide thereby a best practice example of how to evaluate the credibility of PSM estimates. We find that a thorough assessment of the assumptions made renders the data we use not suitable for a credible PSM estimation of the effects of treatment. We conclude that the debate about the impact of Fair Trade certification would greatly benefit from a detailed reporting of credibility checking.