library(idealstan)
# First create data and run a model
to_idealstan <- id_make(score_data = senate114,
outcome = 'cast_code',
person_id = 'bioname',
item_id = 'rollnumber',
group_id= 'party_code',
time_id='date',
high_val='Yes',
low_val='No',
miss_val='Absent')
sen_est <- id_estimate(senate_data,
model_type = 2,
use_vb = TRUE,
vary_ideal_pts='random_walk',
fixtype='vb_partial',
restrict_ind_high = "BARRASSO, John A.",
restrict_ind_low = "WARREN, Elizabeth")
# After running the model, we can plot
# the results of the person/legislator ideal points
id_plot_legis_dyn(sen_est)Function to plot dynamic ideal point models
Description
This function can be used on a fitted idealstan object to plot the relative positions and uncertainties of legislator/persons and bills/items when the legislator/person ideal points are allowed to vary over time.
Usage
id_plot_legis_dyn(
object,
return_data = FALSE,
include = NULL,
item_plot = NULL,
text_size_label = 2,
text_size_group = 2.5,
high_limit = 0.95,
low_limit = 0.05,
line_size = 1,
highlight = NULL,
plot_text = TRUE,
use_ci = TRUE,
plot_lines = 0,
draw_line_alpha = 0.5,
person_line_alpha = 0.3,
person_ci_alpha = 0.8,
item_plot_type = "non-inflated",
show_true = FALSE,
group_color = TRUE,
hpd_limit = 10,
sample_persons = NULL,
plot_sim = FALSE,
use_chain = NULL,
add_cov = TRUE,
...
)
Arguments
object
|
A fitted idealstan object or a named list of idealstan objects if the plot is supposed to show a comparison of different fitted idealstan models (see Time Series vignette)
|
return_data
|
If true, the calculated legislator/bill data is returned along with the plot in a list |
include
|
Specify a list of person/legislator IDs to include in the plot (all others excluded) |
item_plot
|
The value of the item/bill for which to plot its midpoint (character value) |
text_size_label
|
ggplot2 text size for legislator labels |
text_size_group
|
ggplot2 text size for group text used for points |
high_limit
|
A number between 0 and 1 showing the upper limit to compute the posterior uncertainty interval (defaults to 0.95). |
low_limit
|
A number between 0 and 1 showing the lower limit to compute the posterior uncertainty interval (defaults to 0.05). |
line_size
|
Sets the size of the line of the time-varying ideal points. |
highlight
|
A character referring to one of the persons in person_labels that the plot can highlight relative to other persons
|
plot_text
|
If TRUE, will plot person_labels over the lines.
|
use_ci
|
Whether or not high-posterior density intervals (credible intervals) should be plotted over the estimates (turn off if the plot is too busy) |
plot_lines
|
The number of lines of actual draws of time-varying ideal points to draw on the plot. Note that these are grouped by persons. Specific draws selected at random from total number of draws of the estimation. Default is 0. |
draw_line_alpha
|
The opacity of lines plotted over the distribution (should be between 0 and 1, default is 0.5). |
person_line_alpha
|
The transparency level of the time-varying ideal point line |
person_ci_alpha
|
The transparency level of ribbon confidence interval around the time-varying ideal points |
item_plot_type
|
Whether to show the ‘non-inflated’ item/bill midpoints, the ‘inflated’ item/bill midpoints, or produce plots for ‘both’ kinds of models. Defaults to ‘non-inflated’ and will only display an item/bill midpoint if one has been specified in item_plot.
|
show_true
|
Whether to show the true values of the legislators (if model has been simulated) |
group_color
|
If TRUE, use the groups instead of individuals to plot colours
|
hpd_limit
|
The greatest absolute difference in high-posterior density interval shown for any point. Useful for excluding imprecisely estimated persons/legislators from the plot. Leave NULL if you don’t want to exclude any. |
sample_persons
|
If you don’t want to use the full number of persons/legislators from the model, enter a proportion (between 0 and 1) to select only a fraction of the persons/legislators. |
plot_sim
|
Whether to plot the true values of parameters if a simulation was used to generate data (see id_sim_gen)
|
add_cov
|
Whether to add values of hierarchical person-level covariates to the time trends (defaults to TRUE). |
…
|
Other options passed on to plotting function, currently ignored |
Details
This plot shows the distribution of ideal points for the legislators/persons in the model, and also traces the path of these ideal points over time. It will plot them as a vertical line with associated high-density posterior interval (10% to 90%). In addition, if the column index for a bill/item from the response matrix is passed to the item_plot option, then an item/bill midpoint will be overlain on the ideal point plot, showing the point at which legislators/persons are indifferent to voting/answering on the bill/item. Note that because this is an ideal point model, it is not possible to tell from the midpoint itself which side will be voting which way. For that reason, the legislators/persons are colored by their votes/scores to make it clear.