Education maintenance allowance evaluation with administrative data: the impact of the EMA pilots on participation and attainment in post-compulsory education

This report contains the findings of an evaluation of the impact of the Education Maintenance Allowance (EMA) using administrative data. We analyse the effects of its initial piloting - and subsequent extension - on participation in full-time education at ages 16 and 17, and on educational achievement at ages 18 and 19. Furthermore, we conduct subgroup analysis to break down the overall effect by different background characteristics. This allows us to see how the impact of the EMA varies according to characteristics such as sex, ethnic group, and potential indicators of material deprivation and prior academic ability

An assessment of PenSim2

The Department for Work and Pensions (DWP)’s Pensim2 model is a dynamic microsimulation model. The principal purpose of this model is to estimate the future distribution of pensioner incomes, thus enabling analysis of the distributional effects of proposed changes to pension policy. This paper presents the results of an assessment of Pensim2 by researchers at the IFS. We start by looking at the overall structure of the model, and how it compares with other dynamic policy analysis models across the world. We make recommendations at this stage as to how the overall modelling strategy could be improved. We then go on to analyse the characteristics of most of the individual modules which make up Pensim2, examining the data used and the regression and predictions used in each step. The results from this examination are used to formulate a set of short and medium-term recommendations for developing and improving the model. Finally, we look at what might become possible for the model over a much longer time frame – looking towards developing a ‘Pensim3’ model over the next decade or so

Changes in seed dispersal processes and the potential for between-patch connectivity for an arid land daisy

Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal-aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly influence dispersal. We exploited the production of large, persistent dispersal structures (seed heads, henceforth) by Erodiophyllum elderi (Asteraceae), a daisy from arid Australia, to further understand secondary dispersal. Seed head dispersal on and off animal tracks in eight E. elderi patches was monitored for 9.5 months by periodically recording the location of marked seed heads. Sites were located inside a reserve that excludes sheep but not kangaroos, and in a nearby area with both kangaroos and sheep. The distance moved and likelihood of seed head movement was higher in areas with sheep, and especially along animal tracks. There was clear evidence that seed heads were channeled down animal tracks during large rainfall events. Seed head dispersal away from patches occurred to a limited extent via their physical contact with sheep and potentially via wind dispersal. Thus, the advantages of this study system allowed us to demonstrate the two postulated effects of herbivores on dispersal via direct movement of seed heads, and two distinct indirect effects through landscape modification by herbivores from the creation of animal tracks and the denudation of vegetation.Louise M. Emmerson, José M. Facelli, Peter Chesson, Hugh Possingham, and Jemery R. Da

Judicial Citation to Legislative History: Contextual Theory and Empirical Analysis

Judge Leventhal famously described the invocation of legislative history as the equivalent of entering a crowded cocktail party and looking over the heads of the guests for one\u27s friends. The volume of legislative history is so great and varied, some contend, that judges cite it selectively to advance their policy agendas. In this article, we employ positive political and contextual theories of judicial behavior to examine how judges use legislative history. We consider whether opinion-writing judges, as Judge Leventhal might suggest, cite legislative history from legislators who share the same political-ideological perspective as the opinion-writing judge? Or do judges make such choices in a broader context than Judge Levanthal\u27s statement suggests. We posit that an opinion writing judge would cite legislative statements supporting an outcome preferred by the opinion-writing judge, when such statements come from legislators who share the same political-ideological perspective as the opinion-writing judge\u27s colleagues or superiors. This should be so regardless of whether the cited legislator shares the broader perspectives of the opinion-writing judge himself. Put in Leventhal\u27s terms, instead of looking for their own ideological friends, judges look over the heads of the guests for the legislative friends of the judge\u27s colleagues on the bench (or superiors on higher benches). We test this approach with court opinion data gathered from LEXIS and find evidence of hierarchy (high court oversight) and panel (co-members on a court) effects in citation to legislative history, effects that appear related to the political-ideological identification of judges who review or are co-members on a panel of the authoring judge. Specifically, we find that the higher the proportion of Republicans in the reviewing court or sitting on the same three-judge panel, the higher the proportion of legislative history cites that will be to Republican legislators, independent of the political orientation of the authoring judge

Judicial Citation to Legislative History: Contextual Theory and Empirical Analysis

Judge Leventhal famously described the invocation of legislative history as the equivalent of entering a crowded cocktail party and looking over the heads of the guests for one\u27s friends. The volume of legislative history is so great and varied, some contend, that judges cite it selectively to advance their policy agendas. In this article, we employ positive political and contextual theories of judicial behavior to examine how judges use legislative history. We consider whether opinion-writing judges, as Judge Leventhal might suggest, cite legislative history from legislators who share the same political-ideological perspective as the opinion-writing judge? Or do judges make such choices in a broader context than Judge Levanthal\u27s statement suggests. We posit that an opinion writing judge would cite legislative statements supporting an outcome preferred by the opinion-writing judge, when such statements come from legislators who share the same political-ideological perspective as the opinion-writing judge\u27s colleagues or superiors. This should be so regardless of whether the cited legislator shares the broader perspectives of the opinion-writing judge himself. Put in Leventhal\u27s terms, instead of looking for their own ideological friends, judges look over the heads of the guests for the legislative friends of the judge\u27s colleagues on the bench (or superiors on higher benches). We test this approach with court opinion data gathered from LEXIS and find evidence of hierarchy (high court oversight) and panel (co-members on a court) effects in citation to legislative history, effects that appear related to the political-ideological identification of judges who review or are co-members on a panel of the authoring judge. Specifically, we find that the higher the proportion of Republicans in the reviewing court or sitting on the same three-judge panel, the higher the proportion of legislative history cites that will be to Republican legislators, independent of the political orientation of the authoring judge

Body size in ecological networks

Body size determines a host of species traits that can affect the structure and dynamics of food webs, and other ecological networks, across multiple scales of organization. Measuring body size provides a relatively simple means of encapsulating and condensing a large amount of the biological information embedded within an ecological network. Recently, important advances have been made by incorporating body size into theoretical models that explore food web stability, the patterning of energy fluxes, and responses to perturbations. Because metabolic constraints underpin body-size scaling relationships, metabolic theory offers a potentially useful new framework within which to develop novel models to describe the structure and functioning of ecological networks and to assess the probable consequences of biodiversity change. © 2005 Elsevier Ltd. All rights reserved.Peer Reviewe

Predictability of the Arctic sea ice edge

Skillful sea ice forecasts from days to years ahead are becoming increasingly important for the operation and planning of human activities in the Arctic. Here we analyze the potential predictability of the Arctic sea ice edge in six climate models. We introduce the integrated ice-edge error (IIEE), a user-relevant verification metric defined as the area where the forecast and the “truth” disagree on the ice concentration being above or below 15%. The IIEE lends itself to decomposition into an absolute extent error, corresponding to the common sea ice extent error, and a misplacement error. We find that the often-neglected misplacement error makes up more than half of the climatological IIEE. In idealized forecast ensembles initialized on 1 July, the IIEE grows faster than the absolute extent error. This means that the Arctic sea ice edge is less predictable than sea ice extent, particularly in September, with implications for the potential skill of end-user relevant forecasts

Evidence of neutral transcriptome evolution in plants

The transcriptome of an organism is its set of gene transcripts (mRNAs) at a defined spatial and temporal locus. Because gene expression is affected markedly by environmental and developmental perturbations, it is widely assumed that transcriptome divergence among taxa represents adaptive phenotypic selection. This assumption has been challenged by neutral theories which propose that stochastic processes drive transcriptome evolution. To test for evidence of neutral transcriptome evolution in plants, we quantified 18 494 gene transcripts in nonsenescent leaves of 14 taxa of Brassicaceae using robust cross-species transcriptomics which includes a two-step physical and in silicobased normalization procedure based on DNA similarity among taxa. Transcriptome divergence correlates positively with evolutionary distance between taxa and with variation in gene expression among samples. Results are similar for pseudogenes and chloroplast genes evolving at different rates. Remarkably, variation in transcript abundance among root-cell samples correlates positively with transcriptome divergence among root tissues and among taxa. Because neutral processes affect transcriptome evolution in plants, many differences in gene expression among or within taxa may be nonfunctional, reflecting ancestral plasticity and founder effects. Appropriate null models are required when comparing transcriptomes in space and time