get_demand_param_trends: Get Trends (Slopes) of Demand Parameters with respect to...

In beezdemand: Behavioral Economic Easy Demand

Get Trends (Slopes) of Demand Parameters with respect to Continuous Covariates

Description

Computes the trend (slope) of Q0 and/or alpha with respect to one or more continuous covariates using emmeans::emtrends() on a fitted beezdemand_nlme model. Trends are computed on the parameter estimation scale (log10), consistent with how parameters are modeled.

Usage

get_demand_param_trends(
  fit_obj,
  params = c("Q0", "alpha"),
  covariates,
  specs = ~1,
  at = NULL,
  ci_level = 0.95,
  ...
)

Arguments

fit_obj	A beezdemand_nlme object from fit_demand_mixed().
params	Character vector of parameters to analyze: any of "Q0", "alpha". Default c("Q0", "alpha").
covariates	Character vector of continuous covariate names for which to compute trends.
specs	A formula specifying the factors over which to produce trends (e.g., ~ drug for trends by drug; ~ 1 for overall). Default ~ 1.
at	Optional named list to condition variables (factors or continuous) when computing trends (passed through to emmeans::ref_grid).
ci_level	Confidence level for intervals. Default 0.95.
...	Additional args passed to emmeans::emtrends().

Value

A tibble combining trends for each requested parameter and covariate, including columns for grouping factors (from specs), parameter, covariate, trend (slope on log10 scale), and its CI (lower.CL, upper.CL).

Examples

data(ko)
ko$dose_num <- as.numeric(as.character(ko$dose))
fit <- fit_demand_mixed(ko, y_var = "y_ll4", x_var = "x",
                        id_var = "monkey", factors = "drug",
                        equation_form = "zben")
trends <- get_demand_param_trends(fit, covariates = "dose_num",
                                  specs = ~ drug)

beezdemand documentation built on March 3, 2026, 9:07 a.m.