First differences for the matched count families

The discrete-change effect on the expected count E(Y) as variable moves from from to to, holding the other covariates at their sample means. For count_reg this is a single number with a delta-method interval; for the two-part models it is decomposed exactly into extensive (participation / non-structural-zero) and intensive (count) channels that sum to the total.

Usage

# S3 method for class 'gec'
first_difference(object, variable, from, to, level = 0.95, ...)

# S3 method for class 'gec_fe'
first_difference(object, variable, from, to, level = 0.95, ...)

# S3 method for class 'cpb_fe'
first_difference(object, variable, from, to, level = 0.95, ...)

# S3 method for class 'hurdle_gec'
first_difference(
  object,
  variable,
  from,
  to,
  level = 0.95,
  stage = c("both", "participation", "intensity", "zero", "count"),
  ...
)

# S3 method for class 'zi_gec'
first_difference(
  object,
  variable,
  from,
  to,
  level = 0.95,
  stage = c("both", "participation", "intensity", "zero", "count"),
  ...
)

# S3 method for class 'count_reg'
first_difference(object, variable, from, to, level = 0.95, ...)

# S3 method for class 'hurdle_count'
first_difference(
  object,
  variable,
  from,
  to,
  level = 0.95,
  stage = c("both", "participation", "intensity", "zero", "count"),
  ...
)

# S3 method for class 'zi_count'
first_difference(
  object,
  variable,
  from,
  to,
  level = 0.95,
  stage = c("both", "participation", "intensity", "zero", "count"),
  ...
)

Arguments

object

A fitted count_reg, gec, gec_fe, cpb_fe, hurdle_count, zi_count, hurdle_gec, or zi_gec model.

variable

Name of the covariate to change (must be in the model).

from, to

The two values of variable.

level

Confidence level for the delta-method intervals (all methods on this page that can compute one).

...

Unused; unknown arguments error.

stage

For the two-part models, which equation(s) the change is applied to. "both" (default) moves the variable wherever it appears; "intensity"/"count" or "participation"/"zero" moves it in only that equation, holding it at the reference in the other. For a variable in only one equation all options coincide; for a variable in both, "both" gives the total effect and the single-stage options the partial effect through that margin. All component rows are always returned.

Value

A "ud_fd" data frame – the package-wide first-difference contract shared by every first_difference() method: columns component, from, to, diff, lower, upper, method. Single-equation fits return one row (component = "mean"); two-part fits return one row per margin level (binary-stage probability, count-stage mean, marginal mean). method records the uncertainty source per row ("delta", a bootstrap label, or "none" with NA bounds).