Model diagnostic plots

## Usage

```
appraise(model, ...)
# S3 method for class 'gam'
appraise(
model,
method = c("uniform", "simulate", "normal", "direct"),
use_worm = FALSE,
n_uniform = 10,
n_simulate = 50,
type = c("deviance", "pearson", "response"),
n_bins = c("sturges", "scott", "fd"),
ncol = NULL,
nrow = NULL,
guides = "keep",
level = 0.9,
ci_col = "black",
ci_alpha = 0.2,
point_col = "black",
point_alpha = 1,
line_col = "red",
...
)
# S3 method for class 'lm'
appraise(model, ...)
```

## Arguments

- model
a fitted model. Currently only class

`"gam"`

.- ...
arguments passed to

`patchwork::wrap_plots()`

.- method
character; method used to generate theoretical quantiles. Note that

`method = "direct"`

is deprecated in favour of`method = "uniform"`

.- use_worm
logical; should a worm plot be drawn in place of the QQ plot?

- n_uniform
numeric; number of times to randomize uniform quantiles in the direct computation method (

`method = "direct"`

) for QQ plots.- n_simulate
numeric; number of data sets to simulate from the estimated model when using the simulation method (

`method = "simulate"`

) for QQ plots.- type
character; type of residuals to use. Only

`"deviance"`

,`"response"`

, and`"pearson"`

residuals are allowed.- n_bins
character or numeric; either the number of bins or a string indicating how to calculate the number of bins.

- ncol, nrow
numeric; the numbers of rows and columns over which to spread the plots.

- guides
character; one of

`"keep"`

(the default),`"collect"`

, or`"auto"`

. Passed to`patchwork::plot_layout()`

- level
numeric; the coverage level for QQ plot reference intervals. Must be strictly

`0 < level < 1`

. Only used with`method = "simulate"`

.- ci_alpha, ci_col
colour and transparency used to draw the QQ plot reference interval when

`method = "simulate"`

.- point_col, point_alpha
colour and transparency used to draw points in the plots. See

`graphics::par()`

section**Color Specification**. This is passed to the individual plotting functions, and therefore affects the points of all plots.- line_col
colour specification for the 1:1 line in the QQ plot and the reference line in the residuals vs linear predictor plot.

## Note

The wording used in `mgcv::qq.gam()`

uses *direct* in reference to the
simulated residuals method (`method = "simulated"`

). To avoid confusion,
`method = "direct"`

is deprecated in favour of `method = "uniform"`

.

## See also

The plots are produced by functions `qq_plot()`

,
`residuals_linpred_plot()`

, `residuals_hist_plot()`

,
and `observed_fitted_plot()`

.

## Examples

```
load_mgcv()
## simulate some data...
dat <- data_sim("eg1", n = 400, dist = "normal", scale = 2, seed = 2)
mod <- gam(y ~ s(x0) + s(x1) + s(x2) + s(x3), data = dat)
## run some basic model checks
appraise(mod, point_col = "steelblue", point_alpha = 0.4)
## To change the theme for all panels use the & operator, for example to
## change the ggplot theme for all panels
library("ggplot2")
appraise(mod,
point_col = "steelblue", point_alpha = 0.4,
line_col = "black"
) & theme_minimal()
```