find_formula {insight} | R Documentation |
Find model formula
Description
Returns the formula(s) for the different parts of a model (like
fixed or random effects, zero-inflated component, ...). formula_ok()
checks
if a model formula has valid syntax regarding writing TRUE
instead of T
inside poly()
and that no data names are used (i.e. no data$variable
, but
rather variable
).
Usage
find_formula(x, ...)
formula_ok(
x,
checks = "all",
action = "warning",
prefix_msg = NULL,
verbose = TRUE,
...
)
## Default S3 method:
find_formula(x, verbose = TRUE, ...)
## S3 method for class 'nestedLogit'
find_formula(x, dichotomies = FALSE, verbose = TRUE, ...)
Arguments
x |
A fitted model. |
... |
Currently not used. |
checks |
Indicates what kind of checks are conducted when checking
the formula notation. Currently, four different formula specification that
can result in unexpected behaviour of downstream-functions are checked.
|
action |
Should a message, warning or error be given for an invalid
formula? Must be one of |
prefix_msg |
Optional string that will be added to the warning/error
message. This can be used to add additional information, e.g. about the
specific function that was calling |
verbose |
Toggle warnings. |
dichotomies |
Logical, if model is a |
Value
A list of formulas that describe the model. For simple models, only
one list-element, conditional
, is returned. For more complex models, the
returned list may have following elements:
-
conditional
, the "fixed effects" part from the model (in the context of fixed-effects or instrumental variable regression, also called regressors) . One exception areDirichletRegModel
models from DirichletReg, which has two or three components, depending onmodel
. -
random
, the "random effects" part from the model (or theid
for gee-models and similar) -
zero_inflated
, the "fixed effects" part from the zero-inflation component of the model. for models from brms, this component is namedzi
. -
zero_inflated_random
, the "random effects" part from the zero-inflation component of the model; for models from brms, this component is namedzi_random
. -
dispersion
, the dispersion formula -
instruments
, for fixed-effects or instrumental variable regressions likeivreg::ivreg()
,lfe::felm()
orplm::plm()
, the instrumental variables -
cluster
, for fixed-effects regressions likelfe::felm()
, the cluster specification -
correlation
, for models with correlation-component likenlme::gls()
, the formula that describes the correlation structure -
scale
, for distributional models such asmgcv::gaulss()
family fitted withmgcv::gam()
, the formula that describes the scale parameter -
slopes
, for fixed-effects individual-slope models likefeisr::feis()
, the formula for the slope parameters -
precision
, forDirichletRegModel
models from DirichletReg, when parametrization (i.e.model
) is"alternative"
. -
bidrange
, for models of classoohbchoice
(from package DCchoice), which indicates the right-hand side of the bar (the bid-range).
For models from package brms, distributional parameters are also included.
Note
For models of class lme
or gls
the correlation-component is only
returned, when it is explicitly defined as named argument (form
), e.g.
corAR1(form = ~1 | Mare)
Examples
data(mtcars)
m <- lm(mpg ~ wt + cyl + vs, data = mtcars)
find_formula(m)
m <- lme4::lmer(Sepal.Length ~ Sepal.Width + (1 | Species), data = iris)
f <- find_formula(m)
f
format(f)