Prototype tasks: Improving crowdsourcing results through rapid, iterative task design

Low-quality results have been a long-standing problem on microtask crowdsourcing platforms, driving away requesters and justifying low wages for workers. To date, workers have been blamed for low-quality results: they are said to make as little effort as possible, do not pay attention to detail, and lack expertise. In this paper, we hypothesize that requesters may also be responsible for low-quality work: they launch unclear task designs that confuse even earnest workers, under-specify edge cases, and neglect to include examples. We introduce prototype tasks, a crowdsourcing strategy requiring all new task designs to launch a small number of sample tasks. Workers attempt these tasks and leave feedback, enabling the requester to iterate on the design before publishing it. We report a field experiment in which tasks that underwent prototype task iteration produced higher-quality work results than the original task designs. With this research, we suggest that a simple and rapid iteration cycle can improve crowd work, and we provide empirical evidence that requester “quality” directly impacts result quality

The Daemo crowdsourcing marketplace

The success of crowdsourcing markets is dependent on a strong foundation of trust between workers and requesters. In current marketplaces, workers and requesters are often unable to trust each other’s quality, and their mental models of tasks are misaligned due to ambiguous instructions or confusing edge cases. This breakdown of trust typically arises from (1) flawed reputation systems which do not accurately reflect worker and requester quality, and from (2) poorly designed tasks. In this demo, we present how Boomerang and Prototype Tasks, the fundamental building blocks of the Daemo crowdsourcing marketplace, help restore trust between workers and requesters. Daemo’s Boomerang reputation system incentivizes alignment between opinion and ratings by determining the likelihood that workers and requesters will work together in the future based on how they rate each other. Daemo’s Prototype tasks require that new tasks go through a feedback iteration phase with a small number of workers so that requesters can revise their instructions and task designs before launch

Boomerang: Rebounding the consequences of reputation feedback on crowdsourcing platforms

Paid crowdsourcing platforms suffer from low-quality workand unfair rejections, but paradoxically, most workers and requesters have high reputation scores. These inflated scores, which make high-quality work and workers difficult to find,stem from social pressure to avoid giving negative feedback. We introduce Boomerang, a reputation system for crowdsourcing that elicits more accurate feedback by rebounding the consequences of feedback directly back onto the person who gave it. With Boomerang, requesters find that their highly rated workers gain earliest access to their future tasks, and workers find tasks from their highly-rated requesters at the top of their task feed. Field experiments verify that Boomerang causes both workers and requesters to provide feedback that is more closely aligned with their private opinions. Inspired by a game-theoretic notion of incentive-compatibility, Boomerang opens opportunities for interaction design to incentivize honest reporting over strategic dishonesty

Crowd guilds: Worker-led reputation and feedback on crowdsourcing platforms

Crowd workers are distributed and decentralized. While decentralization is designed to utilize independent judgment to promote high-quality results, it paradoxically undercuts behaviors and institutions that are critical to high-quality work. Reputation is one central example: crowdsourcing systems depend on reputation scores from decentralized workers and requesters, but these scores are notoriously inflated and uninformative. In this paper, we draw inspiration from historical worker guilds (e.g., in the silk trade) to design and implement crowd guilds: centralized groups of crowd workers who collectively certify each other’s quality through double-blind peer assessment. A two-week field experiment compared crowd guilds to a traditional decentralized crowd work model. Crowd guilds produced reputation signals more strongly correlated with ground-truth worker quality than signals available on current crowd working platforms, and more accurate than in the traditional model

Revista de Vertebrados de la Estación Biológica de Doñana

Catálogo descriptivo de los anfibios y reptiles de CubaEvolución estacional de la comunidad de aves en un robledal de Sierra NevadaComposición de la comunidad de aves en pinares del Parque Nacional de Doñana (suroeste de España).Alimentación de la pagaza piconegra (Gelochelidon nilotica) en las marismas del GuadalquivirContaminación xenobiótica del Parque Nacional de Doñana. III. Residuos de insecticidas organoclorados, bifenilos policlorados y metales pesados en ciconiformesAlimentación de la lechuza común Tyto alba en la cuenca del Duero, EspañaEstudio de una población rural de (Mus musculus L.) I. La probabilidad de captura y la estima numéricLa reproducción en Gazella dorcasIncidencia del Nemátodo parásito Skrjabingylus Leuckart, 1842 sobre el Mustela en España.Desplazamientos de ungulados silvestres a través de una zona de ecotono en Doñana.Etograma de la cabra montés (Capra pyrenaica) y comparación con otras especies.Sobre comportamiento agresivo de Triturus marmoratus en época de celoEmbarrancamiento masivo de ejemplares de tortuga lad (Dermochelys coriacea L.) en las costas de Ceuta (España, norte de África)Sobre un ejemplar melánico de Podarcis hispanica (Steindachner, 1870)Nuevos datos sobre la distribución de cuatro especies de reptiles en la provincia de Cádiz.Algunos datos sobre la nidificación de Ciconia nigra L. en sierra Morena (S. España)Observación del halcón de Eleonor (Falco eleonorae) en el centro de EspañaNueva localidad de cría del pájaro moscón (Remiz pendulinus) en la Península IbéricaRegistro de aves en el sur de BoliviaNidificación del paiño de Madeira Oceanodroma castro (Harcourt, 1851) en las Islas Canarias.Observación primaveral de Phalaropus fulicarius L. en el SO de EspañaNuevos datos sobre la presencia del nóctulo gigante Nyctalus lasiopterus (Chiroptera, vespertilionidae) en EspañaNote sur l'alimentation de Martes martes a Menorca (Baleares).Peer reviewe

The democracy of Green Infrastructure

With the understanding of nature in terms of ecosystem services and the recognition of the vital role these play for human wellbeing (Millennium Assessment, 2005), the value of the natural realm is scientifically and socially defined while at the same time institutionalised. Within this frame of interpretation, nature is a supplier of provision-ing, regulating, supporting welfare and cultural services, thus becoming not only a life-enabling factor for humanity but also a conceptual construct comparable to cornerstones of democracy, such as equality, freedom and citizenship. The idea of green infrastructure is another recently coined term envisioning nature in cities in the form of a net-work and enabling a broad life-furthering vision of society. Standards for green open spaces embedded in some planning frameworks further state the right for all to a common good. Yet, evidence shows that this common right is not always met. Within the current context of advanced and neoliberal capitalism, green areas are sometimes used as an added financial value for real estate, thus increasing restrictions to their free access and full utilization. In developing countries with young democracies, such as Brazil, this process implies another significant factor of social inequality insofar the restricted access to nature by the poorest people means also diminished food safety, and the jeopardizing of certain cultural practices. In developed countries, loss of land for food production and movements reclaiming the right to the city by squatting unoccupied open spaces to initiate community gar-dens, demonstrates that the access to green spaces is also problematic, although in different ways if compared to developing countries. This chapter contributes to this topic by discussing the inequality in provision of green spaces in informal settlements and social housing development in Brazil, as well as in the globalised north. The chapter concludes with recommendations to enhance democracy through a just provision of nature in cities

Plant Responses to Extreme Climatic Events: A Field Test of Resilience Capacity at the Southern Range Edge

The expected and already observed increment in frequency of extreme climatic events may result in severe vegetation shifts. However, stabilizing mechanisms promoting community resilience can buffer the lasting impact of extreme events. The present work analyzes the resilience of a Mediterranean mountain ecosystem after an extreme drought in 2005, examining shoot-growth and needle-length resistance and resilience of dominant tree and shrub species (Pinus sylvestris vs Juniperus communis, and P. nigra vs J. oxycedrus) in two contrasting altitudinal ranges. Recorded high vegetative-resilience values indicate great tolerance to extreme droughts for the dominant species of pine-juniper woodlands. Observed tolerance could act as a stabilizing mechanism in rear range edges, such as the Mediterranean basin, where extreme events are predicted to be more detrimental and recurrent. However, resistance and resilience components vary across species, sites, and ontogenetic states: adult Pinus showed higher growth resistance than did adult Juniperus; saplings displayed higher recovery rates than did conspecific adults; and P. nigra saplings displayed higher resilience than did P. sylvestris saplings where the two species coexist. P. nigra and J. oxycedrus saplings at high and low elevations, respectively, were the most resilient at all the locations studied. Under recurrent extreme droughts, these species-specific differences in resistance and resilience could promote changes in vegetation structure and composition, even in areas with high tolerance to dry conditions.This study was supported by Ministerio de Ciencia e Innovación (Spanish Government) Projects CGL2008-04794 and CGL2011-29910 to R.Z., and by grant FPU-MEC (AP2005-1561) to A. H

La Red Internacional de Inventarios Forestales (BIOTREE-NET) en Mesoamérica: avances, retos y perspectivas futuras

Conservation efforts in Neotropical regions are often hindered by lack of data, since for many species there is a vacuum of information, and many species have not even been described yet. The International Network of Forest Inventory Plots (BIOTREE-NET) gathers and facilitates access to tree data from forest inventory plots in Mesoamerica, while encouraging data exchange between researchers, managers and conservationists. The information is organised and standardised into a single database that includes spatially explicit data. This article describes the scope and objectives of the network, its progress, and the challenges and future perspectives. The database includes above 50000 tree records of over 5000 species from more than 2000 plots distributed from southern Mexico through to Panama. Information is heterogeneous, both in nature and shape, as well as in the geographical coverage of inventory plots. The database has a relational structure, with 12 inter-connected tables that include information about plots, species names, dbh, and functional attributes of trees. A new system that corrects typographical errors and achieves taxonomic and nomenclatural standardization was developed using The Plant List (http://theplantlist.org/) as reference. Species distribution models have been computed for around 1700 species using different methods, and they will be publicly accessible through the web site in the future (http://portal.biotreenet.com). Although BIOTREE-NET has contributed to the development of improved species distribution models, its main potential lies, in our opinion, in studies at the community level. Finally, we emphasise the need to expand the network and encourage researchers willing to share data and to join the network and contribute to the generation of further knowledge about forest biodiversity in Neotropical regions