Bias reduction of maximum likelihood estimates

Firth, David

doi:10.1093/biomet/80.1.27

Cited by 3,434 publications

(1,903 citation statements)

References 27 publications

Supporting

Mentioning

1,860

Contrasting

Unclassified

Order By: Relevance

“…We considered the sample size of 90 border cells to be too small and therefore used a penalized maximum likelihood estimation. This method results in approximately unbiased estimates of coefficients even with small sample sizes and separation issues (Allison 2008;Firth 1993;Heinze and Schemper 2002). We built three separate models; the first model used all border crossing data by pooling both entry sites and exit sites, the second one used all entry crossings, and the third one used all exit crossings.…”

Section: Logistic Regression Models Using Penalized Maximum Likelihoomentioning

confidence: 99%

Understanding site selection of illegal border crossings into a fenced protected area: a rational choice approach

2018

View full text Add to dashboard Cite

This study investigates illegal border crossings by rhino poachers into a fenced reserve in South Africa, comparing journeys to and after crime using a rational choice approach. Using various regression models, our analysis indicates poachers prefer to enter and exit the reserve near high rhino densities, while high road densities outside the reserve increase the odds of an illegal entry. The results also show that half of the incursions occurred at a single location, leading us to describe the special circumstances of this outlier. The study lays a foundation for understanding the location choices poachers make and presents a methodology that can be replicated in other reserves.

show abstract

Section: Logistic Regression Models Using Penalized Maximum Likelihoomentioning

confidence: 99%

Understanding site selection of illegal border crossings into a fenced protected area: a rational choice approach

2018

View full text Add to dashboard Cite

show abstract

“…The statistical significance of the effect size for D 50 was determined by the p-value of a t-test. Statistical significance for percent fine sediment was assessed by logistic regression using a bias correction for low numbers of successes (Firth 1993).…”

Section: Power To Detect Changes In Substrate Compositionmentioning

confidence: 99%

Design considerations for community-based stream monitoring to detect changes in Pacific salmon habitats

Lagasse¹,

Ou²,

Honka³

et al. 2014

E&S

View full text Add to dashboard Cite

ABSTRACT. Communities in the Great Bear Rainforest of British Columbia, Canada are highly dependent on Pacific salmon (Oncorhynchus spp.) and the watersheds that support them, yet current monitoring efforts are likely inadequate for detecting changes in stream habitats that may affect salmon populations. The Coastal First Nations Regional Monitoring System is attempting to address these information gaps through a new stream assessment program that collects baseline information and tracks changes in stream habitats. Using the program's monitoring protocol, we assessed the habitat characteristics of eight streams within the Koeye and Namu watersheds, then used a statistical power simulation to determine within-stream sampling requirements for detecting changes in substrate composition that may affect salmon habitat suitability. We also assessed resource constraints and perceived threats to stream habitats via questionnaires to coastal First Nations' stewardship staff. Results suggest that the current recommended sample size of 6 withinstream transects has low statistical power for detecting biologically significant changes in fine sediment. Given limited monitoring resources, we recommend higher transect sampling intensities within productive riffle-pool streams, but an emphasis on monitoring site level characteristics, such as large woody debris and pool volume, in less productive, high gradient cascade-pool streams. Questionnaire results highlight the need for flexibility and local adaptation in monitoring efforts because of differences in resource constraints among First Nations communities. If successfully implemented, the stream assessment program can integrate local knowledge with western science to inform ecosystem-based management of watersheds within the Great Bear Rainforest.

show abstract

“…To test the hypothesis that tail-flagging deters snakes from striking, we used a logistic regression with penalized maximum-likelihood estimates in R ('logistf ' package in R; v. 2.13.0) [28][29][30]. Specifically, we examined whether snake strike behaviour (binary response variable) is a function of whether squirrels tail-flagged (binary explanatory variable) and included distance to snake, both as a covariate and interaction term, since it is a known determinant of snake strike success [27].…”

Section: (D) Strike Behaviourmentioning

confidence: 99%

Ground squirrel tail-flag displays alter both predatory strike and ambush site selection behaviours of rattlesnakes

Barbour

Clark

2012

Proc. R. Soc. B.

View full text Add to dashboard Cite

Many species approach, inspect and signal towards their predators. These behaviours are often interpreted as predator-deterrent signals-honest signals that indicate to a predator that continued hunting is likely to be futile. However, many of these putative predator-deterrent signals are given when no predator is present, and it remains unclear if and why such signals deter predators. We examined the effects of one such signal, the tail-flag display of California ground squirrels, which is frequently given both during and outside direct encounters with northern Pacific rattlesnakes. We video-recorded and quantified the ambush foraging responses of rattlesnakes to tail-flagging displays from ground squirrels. We found that tail-flagging deterred snakes from striking squirrels, most likely by advertising squirrel vigilance (i.e. readiness to dodge a snake strike). We also found that tail-flagging by adult squirrels increased the likelihood that snakes would leave their ambush site, apparently by elevating the vigilance of nearby squirrels which reduces the profitability of the ambush site. Our results provide some of the first empirical evidence of the mechanisms by which a prey display, although frequently given in the absence of a predator, may still deter predators during encounters.

show abstract

Bias reduction of maximum likelihood estimates

Cited by 3,434 publications

References 27 publications

Understanding site selection of illegal border crossings into a fenced protected area: a rational choice approach

Understanding site selection of illegal border crossings into a fenced protected area: a rational choice approach

Design considerations for community-based stream monitoring to detect changes in Pacific salmon habitats

Ground squirrel tail-flag displays alter both predatory strike and ambush site selection behaviours of rattlesnakes

Contact Info

Product

Resources

About