Questions tagged [mgcv]

Question 1

I am running a GAMM model to look at the effect of temperature on the daily patterns (in radians) of an animal's movement (step length). The data is hourly, however there are individuals with hours, ...

Question 2

I've got a dataset describing the infestation of an insect on plants in a very large area. The data were collected using several transects. Each transect is composed of 4 plots, with multiple plants ...

Question 3

It might be a bold question, but I wanted to be sure that I am on the right track with my thoughts, since I am no mathematician or something close :) When using GAMs with a smooth-factor interaction, ...

Question 4

Recently, I was asked about the partial R2 of predictors or how much each term contributes to the overall explanatory "power" of the model. I think it was a question stemming from the ...

Question 5

I’m working on my master’s thesis and decided in advance to use a GAM (using mgcv in R). I won't have a lot of data, but I think just enough to model it and just note that there are strong limitations ...

Question 6

I have a survival model for a long term mark-recap study that I am trying to apply to several populations. I have been trying to follow Pedersen et al 2019 for this, but I have variables for which I ...

Question 7

I have trial-level data from 329 participants aged 18–79. Each participant completed 90 trials of an association task. Each trial includes: a within-subject factor Condition (3 levels: A, B, C; 30 ...

Question 8

I am using GAMMs to model the probability of occurrence of a species, applying logistic regressions with mgcv::bam() to presence-pseudoabsence data. The dataset ...

Question 9

I am fitting the following GAM model. My response variable is aggregated counts of disease incidence at the county-level. I used log(population) as an offset. If I use it this way, I learned that it ...

Question 10

I fit the following hierarchical gam. My response variable here is Foliar total phosphorus. I have about 20 years of annual data (no gaps) and about 3-5 replicates (collections) per site. I wanted to ...

Question 11

I have a dataset of brain signals that were recorded simultaneously from several brain regions while participants performed a cognitive task. I have two categorical predictors (recording site, ...

Question 12

I’m fitting hierarchical generalized additive model (HGAMs) to model temporal trends while accounting for nested structure in the data. The goal here is to specify Site nested within Basin. The model ...

Question 13

Goal: Annual TP at 4 sites (18 years, ~3 plots per site per year). I fit a hierarchical GAM with a global smooth over Year plus site-specific smooths (factor–smooth interaction). I want to identify ...

Question 14

I'm in need of some advice on how to account for residual dependence in a fitted GAM that doesn't appear to be driven by temporal structure in the data. In summary, I am working with a long-term ...

Question 15

I’ve been running Generalized Additive Models (GAMs) to explore temporal trends in my soil phosphorus data. I have 20 years of data at each site. I'm considering either modeling individual GAMs for ...

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Questions tagged [mgcv]

GAMM model with corCAR1() run-time?

(simulated) residual check for binary GAMM

comparing smooths in smooth-factor interaction: can I include the intercept?

Partial "R2" or Deviance Explained for GAMs?

Can I use a GAM for my data even though it's almost binary?

specification of hierarchical GAMs with ti() interactions

Modeling whether age modulates within-subject condition differences using bam() in R

Dealing with high concurvity and variable selection in GAMMs with imbalanced data (mgcv::bam)

Why do we say that we model the rate instead of counts if offset is included?

Hierarchical GAM: gam.check small k-index p-value, no acf issues

Three-way Interactions within GAMMs and appropriate follow-up analyses

Three-Level Hierarchical GAM

Detecting periods of significant change in a hierarchical GAM (HGAM) (Tweedie, log link)

Unaccounted for residual dependence in hierarchical GAM

Using GAMs and Checking for Autocorrelation in Time Series Data

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