Posted in 2026
Heteroscedastic Bayesian Robust Regression
- 30 April 2026
The PyMC gallery has two robust regression notebooks: one with a Student-t likelihood (pymc-examples:GLM-robust) and one with the Hogg (2010) signal-vs-noise mixture (pymc-examples:GLM-robust-with-outlier-detection). Both protect against vertical outliers (points with unusual response values), but neither defends against leverage points: observations far from the bulk of the predictor space, which can drag the regression line even under a heavy-tailed likelihood.
Estimating species distributions with occupancy models
- 06 January 2026
Estimating where species live is one of the most common tasks in ecology. Recreational birders know that every field guide includes a range map showing where a species can be found, as well as habitat information to help locate the animals. For example, a field guide for Swiss birds might tell you that Red Crossbills (Loxia curvirostra) are most likely found in forests at intermediate elevations. Both of these tasks–mapping ranges and estimating habitat relationships–fall under the umbrella of species distribution modeling.