do_bma {stgam}

Undertake undertake coefficient averaging using Bayesian Model Avergaing (BMA), weighting different models by their probabilities

Description

Undertake undertake coefficient averaging using Bayesian Model Avergaing (BMA), weighting different models by their probabilities

Usage

do_bma(model_table, terms, thresh = 0.1, relative = FALSE, input_data)

Arguments

model_table

a table of competing models generated by gam_model_probs

terms

a vector of names starting with "Intercept" plus the names of the covariates used in the GAM model (these are the names of the variables in data )

thresh

a probability threshold value above which to combine competing models

relative

a logical to indicate whether the probabilities in data are relative (Pr(M)) or absolute (Pr(M|D))

input_data

the input data with a named Intercept term, in data.frame, tibble or sf format

Value

A matrix of the probability weighted averaged coefficient estimates from multiple models.

Examples

library(cols4all)
library(dplyr)
library(sf)
library(glue)
library(purrr)
library(mgcv)
library(sf)
library(ggplot2)
# data
data(productivity)
input_data = productivity |> filter(year == "1970") |> mutate(Intercept = 1)
# create and evaluate multiple models
svc_res_gam = evaluate_models(input_data, STVC = FALSE)
# determine their probabilities
mod_comp_svc <- gam_model_probs(svc_res_gam)
# combine the model coefficients
svc_bma <- do_bma(mod_comp_svc,
                  terms = c("Intercept", "unemp", "pubC"),
                  thresh = 0.1,
                  relative = FALSE,
                  input_data = input_data)
head(svc_bma)
# join back to spatial layer
data(us_data)
svc_bma_sf <-
us_data |>
select(GEOID) |>
left_join(productivity |>
  filter(year == "1970") |>
  select(GEOID, year) |>
  cbind(svc_bma)) |>
  relocate(geometry, .after = last_col())
# and map
tit =expression(paste(""*beta[`Public Capital`]*" "))
ggplot(data = svc_bma_sf, aes(fill=pubC)) +
  geom_sf() +
  scale_fill_continuous_c4a_div(palette="brewer.yl_or_rd",name=tit) +
  coord_sf() +
  theme_linedraw()