# Plot of marginal APC effects based on an estimated GAM model

Source:`R/plot_partialAPCeffects.R`

`plot_marginalAPCeffects.Rd`

Plot the marginal effect of age, period or cohort, based on an APC model
estimated as a semiparametric additive regression model with `gam`

or `bam`

.
This function is a simple wrapper to `plot_partialAPCeffects`

,
called with argument `hide_partialEffects = TRUE`

.

## Usage

```
plot_marginalAPCeffects(
model,
dat,
variable = "age",
vlines_vec = NULL,
plot_CI = FALSE,
return_plotData = FALSE
)
```

## Arguments

- model
Optional regression model estimated with

`gam`

or`bam`

to estimate a smoothed APC surface. Only used if`y_var`

is not specified.- dat
Dataset with columns

`period`

and`age`

. If`y_var`

is specified, the dataset must contain the respective column. If`model`

is specified, the dataset must have been used for model estimation with`gam`

or`bam`

.- variable
One of

`c("age","period","cohort")`

, specifying the temporal dimension for which the partial effect plots should be created.- vlines_vec
Optional numeric vector of values on the x-axis where vertical lines should be drawn. Can be used to highlight the borders of specific age groups, time intervals or cohorts.

- plot_CI
Indicator if 95% confidence intervals should be plotted. Defaults to FALSE.

- return_plotData
If TRUE, a list of the datasets prepared for plotting is returned instead of the ggplot object. The list contains one dataset each for the overall effect (= evaluations of the APC surface to plot the partial effects) and for each marginal APC effect (no matter the specified value of the argument

`variable`

). Defaults to FALSE.

## References

Weigert, M., Bauer, A., Gernert, J., Karl, M., Nalmpatian, A.,
Küchenhoff, H., and Schmude, J. (2021). Semiparametric APC analysis of
destination choice patterns: Using generalized additive models to quantify
the impact of age, period, and cohort on travel distances.
*Tourism Economics*. doi:10.1177/1354816620987198.

## Author

Alexander Bauer alexander.bauer@stat.uni-muenchen.de, Maximilian Weigert maximilian.weigert@stat.uni-muenchen.de

## Examples

```
library(APCtools)
library(mgcv)
data(travel)
model <- gam(mainTrip_distance ~ te(age, period), data = travel)
plot_marginalAPCeffects(model, dat = travel, variable = "age")
# mark specific cohorts
plot_marginalAPCeffects(model, dat = travel, variable = "cohort",
vlines_vec = c(1966.5,1982.5,1994.5))
```