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Andrew Bennett help us think about what steps are necessary to use case studies to identify causal relationships and draw contingent generalizations. He suggests that case study research employs Bayesian logic rather than frequentist logic. “Bayesian logic treats probabilities as degrees of belief in alternative explanations, and it updates initial degrees of belief (called ‘priors’) by using assessments of the probative value of new evidence vis-à-vis alternative explanations (the updated degree of belief is known as the ‘posterior’).” Bennett sketches four approaches: generalization from ‘typical’ cases, generalization from most- or least-likely cases, mechanism-based generalization, and typological theorizing, with special attention to the last two. The study of deviant, or outlier, cases and cases that have high values on the independent variable of interest (theory of change) may prove helpful, Bennett suggests, aiding the identification of scope conditions, new explanations, and omitted variables.
“Process tracing and program evaluation, or contribution analysis, have much in common, as they both involve causal inference on alternative explanations for the outcome of a single case,” Bennett says. “Evaluators are often interested in whether one particular explanation – the implicit or explicit theory of change behind a program – accounts for the outcome. Yet they still need to consider whether exogenous non-program factors … account for the outcome, whether the program generated the outcome through some process other than the theory of change, and whether the program had additional or unintended consequences, either good or bad.” Bennett discusses how to develop a process-tracing case study to meet these demands and walks the reader through several key elements of this enterprise, including types of confounding explanations and the basics of Bayesian analysis.
Diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), a globally important pest of Brassicaceae crops, migrates into all provinces of Canada annually. Life tables were used to determine the mortality levels contributed by the parasitoid complexes associated with diamondback moth in British Columbia, Ontario, Prince Edward Island, and insular Newfoundland. Overall, diamondback moth populations showed high generational mortality (> 90%) in all provinces, although parasitism levels were generally low. The net reproductive rate of increase in diamondback moth was less than 1.0 (populations declined) in both years in British Columbia and in each of two years in Newfoundland and Ontario, but it was greater than 1.0 in all three years in Prince Edward Island. Lower parasitism levels were found in Prince Edward Island (3.0–6.3%) compared with other provinces (8.4–17.6%, except one year in British Columbia). Diadegma insulare was the main larval parasitoid found; it was present in all provinces. Microplitis plutellae was present in all provinces except British Columbia. Oomyzus sokolowskii was found in British Columbia and Ontario. The parasitoid community documented from sentinel sampling was less diverse than that found through destructive sampling. Hypotheses are provided to explain the presence of major parasitoids. Increasing larval parasitism would have the largest effect on diamondback moth population growth in Canada.
Diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), was first recorded in North America from Europe about 150 years ago and can be a significant pest of canola in Western Canada. Because parasitism of P. xylostella in Canada is generally low, the introduction of one or more additional exotic parasitoids from Europe is being considered to increase the suppression of P. xylostella populations. Life table studies to determine the impact of parasitoids on diamondback moth populations in Europe were conducted in northwestern Switzerland in 2014–2016. Net reproductive rates were found to be less than one in seven out of eight life tables, suggesting that P. xylostella populations in Switzerland are mostly driven by immigration and recolonisation. In total, seven primary parasitoid species and one hyperparasitoid were associated with diamondback moth. Pupal parasitism by D. collaris reached up to 30%, but because generational mortality was mainly driven by abiotic mortality factors and predation of larvae, the overall contribution of pupal parasitism was low (< 6%). In regions of Canada, where P. xylostella may have increasing populations and low larval mortality, the addition of D. collaris may be a promising approach. Life table studies across Canada are necessary to determine the need for such intervention.
Bayesian analysis has emerged as a rapidly expanding frontier in qualitative methods. Recent work in this journal has voiced various doubts regarding how to implement Bayesian process tracing and the costs versus benefits of this approach. In this response, we articulate a very different understanding of the state of the method and a much more positive view of what Bayesian reasoning can do to strengthen qualitative social science. Drawing on forthcoming research as well as our earlier work, we focus on clarifying issues involving mutual exclusivity of hypotheses, evidentiary import, adjudicating among more than two hypotheses, and the logic of iterative research, with the goal of elucidating how Bayesian analysis operates and pushing the field forward.
In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process—the Qualitative Transparency Deliberations (QTD)—involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups’ final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net, the reports unpack transparency’s promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports—the full versions of which can be found in the Supplementary Materials—offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate—as understood by relevant research communities—to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu.1
Families who attract the attention of child protection services most often have ongoing lived experiences of poverty, gender-based domestic and family violence, problematic substance use and, sometimes, formally diagnosed mental health conditions. Without broader contextual knowledge and understanding, particularly regarding ongoing poverty, decision-making by child protection workers often leads to the removal of children, while the family’s material poverty and experiences of violence remain unaddressed. Case studies are a common tool to succinctly capture complex contexts. In this article, we make explicit, through case examples and analysis, how poverty is almost always the backdrop to the presence of worrying risk factors before and during child protection intervention. Further, we expose the existential poverty that parents live with after they lose their children into care and which invariably exacerbates material poverty. In the final section, we consider the multi-faceted organisational poverty that blights the work environment of child protection workers, and we suggest strategies for improved practice with families living in poverty.
This study recorded distribution and size of alfalfa weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) populations in Saskatchewan, Canada, from 2001 to 2014. The spread of alfalfa weevil across the province, originally southwest to southeast, was northward and westward during this time. By 2014, only northwestern and west central areas remained relatively alfalfa weevil free. From a minor pest in 2001, the alfalfa weevil increased to be the principal insect pest of alfalfa (Medicago sativa Linnaeus; Fabaceae) in 2014. The parasitoid Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneumonidae) had a similar distribution. Other parasitoids collected included Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae) and Microctonus colesi Drea (Hymenoptera: Braconidae). Conservation of these parasitoids is an important step in maximising their effectiveness as alfalfa weevil biocontrol agents. Molecular sequencing of the DNA barcoding region of specimens identified morphologically as B. curculionis indicated moderately high levels of sequence divergence among specimens (up to 5.8%); however, interspecific genetic variation between other species of Bathyplectes Förster was also high. Therefore, we conclude that B. curculionis was the only Bathyplectes species collected in our study. An illustrated key to the described species of Bathyplectes in North America is provided, as well as DNA barcodes of most species, including five distinct barcodes in the Bathyplectes curculionis–B. exiguus (Gravenhorst) species complex.
It is no exaggeration to say that sympathy is the founding principle of the poems collected in both the first and second editions of the Lyrical Ballads. Together with the associated and overlapping affective impulses of compassion, pity, identification, and what we tend now to call ‘empathy’, sympathy, or its absence, is a central organising impulse of almost every poem in the collection. Sympathy – a feeling for or feeling with – is expressed and explored in various ways and with, or towards, different kinds of individuals or objects (including animals and inanimate objects), but is consistently the focus of poem after poem. As Wordsworth comments in the final poem in the 1800, two-volume edition of Lyrical Ballads, the ‘power / Of Nature’ has led him to ‘feel / For passions that were not my own’ and thereby to think ‘On man, the heart of man, and human life’ (LB ‘Michael’, 28–31).
A rearing study of egg and larval parasitoids of hemlock looper (Lambdina fiscellaria (Guenée); Lepidoptera: Geometridae) was undertaken during an outbreak of this pest in Labrador, Newfoundland and Labrador, Canada. Six parasitoid species were found: Telenomus coloradensis Crawford and T. droozi Muesebeck (Hymenoptera: Platygastridae), Winthemia occidentis Reinhard and Blondelia eufitchiae (Townsend) (Diptera: Tachinidae), as well as one species of Phobocampe Förster and Mesochorus vittator (Zetterstedt) (Hymenoptera: Ichneumonidae). None of them was a new Canadian record. To facilitate understanding of the regional parasitoid assemblage in Labrador, we compiled all published records in Canada and collated all specimen records from the Canadian National Collection of Insects, Arachnids, and Nematodes (Ottawa, Ontario, Canada). This comprehensive list will aid researchers interested in potential biological control candidates for hemlock looper.
A controversy at the 2016 IUCN World Conservation Congress on the topic of closing domestic ivory markets (the 007, or so-called James Bond, motion) has given rise to a debate on IUCN's value proposition. A cross-section of authors who are engaged in IUCN but not employed by the organization, and with diverse perspectives and opinions, here argue for the importance of safeguarding and strengthening the unique technical and convening roles of IUCN, providing examples of what has and has not worked. Recommendations for protecting and enhancing IUCN's contribution to global conservation debates and policy formulation are given.