get_obs_dens: Generate observed densities

In geocausal: Causal Inference with Spatio-Temporal Data

Generate observed densities

Description

'get_obs_dens()' takes a hyperframe and returns observed densities. The output is used as propensity scores.

Usage

get_obs_dens(hfr, dep_var, indep_var, ngrid = 100, window)

Arguments

hfr	hyperframe
dep_var	The name of the dependent variable. Since we need to obtain the observed density of treatment events, 'dep_var' should be the name of the treatment variable.
indep_var	vector of names of independent variables (covariates)
ngrid	the number of grid cells that is used to generate observed densities. By default = 100. Notice that as you increase 'ngrid', the process gets computationally demanding.
window	owin object

Details

'get_obs_dens()' assumes the poisson point process model and calculates observed densities for each time period. It depends on 'spatstat.model::mppm()'. Users should note that the coefficients in the output are not directly interpretable, since they are the coefficients inside the exponential of the poisson model.

Value

list of the following: * 'indep_var': independent variables * 'coef': coefficients * 'intens_grid_cells': im object of observed densities for each time period * 'estimated_counts': the number of events that is estimated by the poisson point process model for each time period * 'sum_log_intens': the sum of log intensities for each time period * 'actual_counts': the number of events (actual counts)

geocausal documentation built on April 3, 2025, 8:46 p.m.