This paper provides the first estimates of the determinants of the duration of employer search in the UK. We model duration until a vacancy is either successfully filled or withdrawn from the market. The econometric techniques deal with multiple vacancies and unobserved heterogeneity (dependent risks), using flexible and parametric baseline hazards. The hazards to filling and withdrawing exhibit negative and positive duration dependence respectively, implying that the conditional probability of successful employer search decreases with duration. We also find that nonmanual vacancies are less likely to fill, consistent with there being skill shortages in the sample period. Copyright (c) The London School of Economics and Political Science 2007.

A two-dimensional probabilistic model has been developed to estimate the short-term dietary exposure of UK consumers to migrants from food packaging materials. The current EU approach uses a default scenario of assuming that all individuals are 60 kg weight and consume 1 kg of food packaged in the material of interest per day. Using four UK National Dietary and Nutrition Surveys comprising 4-7 day dietary records for different age groups and survey years, a sample representative of the UK population has been obtained consuming around 4200 different food items. Each survey provides records for around 2000 individuals and supplies detailed information on the consumption of food and data on sex, height and socio-economic status which may be used to analyse the exposure of selected groups within the community. As a result we are able to address the variation in consumption of food amongst individuals, and account for actual body weights providing a more accurate representation of the 'true' exposure. The migrants bisphenol A diglycidyl ether (BADGE), di-2-ethylhexyl adipate (DEHA) and styrene were considered as specimen compounds although the methodology employed has the flexibility to adapt to other migrants and packaging types and indeed other food contaminants. Exposure for each individual is estimated by calculating and summing the individual exposure from each item in their diet, and is repeated for all individuals in each survey to produce a distribution of exposures for the population. The packaging type of each food item is assigned by utilizing known packaging types from the database or, by sampling from a distribution based upon market share information. The parameters contributing towards the exposure from a packaged dietary item are migrant concentration and item weight. Distributions are used to represent the inherent variation and uncertainty affecting these parameters. Where data on concentrations for a particular type of food are lacking, expert judgement is used to extrapolate from available data for other food types. The model can also be run using only migration data for food simulants. In this case, concentrations expected for each of the food items are assigned based on the data for the relevant food simulant. The primary outputs of the model are distributions of estimated daily intakes for the selected population. Each distribution gives the variation across the population subject to the uncertain parameters sampled in that iteration of the model. Analysing the ensemble of distributions allows us to obtain the confidence limits around estimates for percentiles due to the uncertainties. The probabilistic approach allows sensitivity analysis to evaluate the relative importance of the input parameters and places confidence bounds on the outputs to show the effect of the uncertainties and the contribution of each food type toward the overall exposure.

This empirical paper investigates skill formation in the youth labour market. Using eventhistory data collected from the administrative records of Lancashire Careers Service, we model training preferences' formed at school by young people and`training destinations', ie the occupation of the ®rst job/training scheme. We also model the duration of the individual's ®rst unemployment spell. Competing risks models with¯exible piece-wise linear baseline hazards and unobserved heterogeneity are estimated. There is evidence of occupational segregation by gender and an excess demand for general training. Outcomes are mainly determined by examination performance, ethnicity and whether disadvantaged.There is considerable concern about the quality and quantity of workforce skills in many advanced countries. This concern stems from the view that a highly skilled workforce is necessary for survival in an increasingly competitive world market, and from the view that the pace of skill-biased technological change generates a need for an adaptable and¯exible workforce. 1 In Britain, the problem is even more acute, as it is well-established that Britain suffers from a so-called`skills gap' in comparison with some of its main international competitors, such as Germany.In Britain, the skills gap is widest at the intermediate level, where there are too few craft and technician workers. These skills are often acquired early in a worker's career, via apprenticeships, traineeships and the Youth Training (YT) programmes, the last of these having attracted considerable amounts of public funding by successive British governments. 2 A popular current view is that the problem is due to a lack of demand for vocational quali®cations by young people. 3 For some individuals, YT is a direct route to a wide range of intermediate level occupations, which provide training leading to the acquisition of certi®cated general transferable skills (hereafter`general training').

We estimate the stock‐flow matching model using micro‐level data from a well‐defined labor market. Using a dataset of complete labor‐market histories for both sides of the market, we estimate hazard functions for job‐seekers and vacancies. We find that the stock of new vacancies has a significant positive impact on the job‐seeker hazard, over and above that of the total stock of vacancies. There is an even stronger robust result for vacancy hazards. Thus we find evidence in favor of stock‐flow matching, even when controlling for unobserved search heterogeneity and stratifying into submarkets defined by location and occupation.

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