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Record W2620778781 · doi:10.1016/j.spasta.2017.05.001

A local-EM algorithm for spatio-temporal disease mapping with aggregated data

2017· article· en· W2620778781 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.
aboutThe title or abstract carries a Canadian signal from the geographic lexicon.

Bibliographic record

VenueSpatial Statistics · 2017
Typearticle
Languageen
FieldEconomics, Econometrics and Finance
TopicSpatial and Panel Data Analysis
Canadian institutionsDalhousie UniversityCancer Care Nova ScotiaUniversity of TorontoSt. Michael's HospitalInstitute for Clinical Evaluative Sciences
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsExpectation–maximization algorithmSmoothingPoint processAlgorithmPopulationPoisson distributionComputer scienceBoundary (topology)CovariateA priori and a posterioriMaximizationConstraint (computer-aided design)StatisticsEconometricsMathematicsData miningMathematical optimizationMaximum likelihoodDemography

Abstract

fetched live from OpenAlex

Spatial data on disease incidence locations are often aggregated to regional counts to preserve privacy, and spatio-temporal modelling of such can be problematic when there are boundary changes over the study period. Here an inhomogeneous Poisson process with intensity depending on variations in population (known a priori) and a smoothly varying relative risk is estimated with a local-Expectation–Maximization (or local-EM) algorithm. Using incidence data for male bladder cancer in Nova Scotia, Canada, the question of whether the data are consistent with spatially varying but temporally constant relative risk is examined. Areas where there is evidence that relative risk is substantially greater than 1 are identified with the intention of assessing the possible presence of environmental risk factors. This paper extends existing work by incorporating a temporally varying risk surface and an explicit data structure which contains a mixture of point locations and locations aggregated to non-nested areas. This added flexibility allows the modelling of data amalgamated from different sources and collected over many years. While local-EM leads naturally to an Expectation–Maximization–Smoothing algorithm, the extension to mixtures of aggregations leads to a modified algorithm that includes an additive term at every iteration to account for observed point locations.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.858
Threshold uncertainty score0.988

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0010.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.077
GPT teacher head0.267
Teacher spread0.190 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it