A Declarative Interface for Statistical Inference
What does {statim} mean?
statim is a Latin word for “immediately, at once”. Its
prefix, stat (as in statistics), is where the domain this
package lives in. This can be interpreted as: you declare what
statistical inference you want to perform, then {statim}
immediately delivers how.
R has a dedicated rich ecosystem in statistics. Statistical inference in general is served by an assortment of disconnected functions: the functions you’re looking for may exist but they are scattered across different packages.
R gained a grammar for graphics ({ggplot2}), and one for
data manipulation ({dplyr}). And then there’s
{statim}, an attempt to re-imagine the “grammar of
statistical inference” from the ground up. The core idea of
{statim} in general is it’s fully declarative, and that any
inferential procedure can be described in three
steps.
What makes {statim} composable for statistical
workflows is the verbs and the accessibility of the
methods you’re looking for. For example, you want to write a t-test
pipeline, and you want to use the classical one and then the permutation
method. {statim} lets you do that with
via("<method_name>"), and while you can use t-test
from default (classical), you can access its permutation
method through ... |> via("permute") with one line of
code only. You won’t need you to do a lot of work (which sometimes
require rewriting your code), just a single addition to the syntax.
# Classical t-test
sleep |>
define_model(x_by(extra, group)) |>
prepare_test(T_TEST) |>
conclude()
# Permutation t-test
sleep |>
define_model(x_by(extra, group)) |>
prepare_test(T_TEST) |>
# Here, one line added
# Nothing else changed
via("permute", n = 1000L) |>
conclude()For a quick result, a one-liner or an eager form skips the piped syntax entirely:
# Only works for `<stat_fn>` functions
T_TEST(x_by(extra, group), sleep)The nuanced downside of eager forms is that they are not supported
with its main semantics that is, for example, (1) recalibrating /
switching off into different methods from the same estimation method
with via() and (2) do not support post-execution output
manipulation.
Visit vignette("statim") to get started.
The package is designed around three ideas:
Composability: the simplest way to write
{statim} has two forms: the eager form and the
grammar/piped syntax form. The eager form skips the verbs and cannot be
recalibrated, only skips to the output. On the other hand, the
grammar/piped syntax form relies on verbs and lazy loading, which comes
with the recalibration of the estimation method with a single
via() call, and the execution of the lazy-loaded pipeline
with conclude().
A shared grammar: Only applied on the main
{statim} semantics: piped/grammar syntax.
define_model() => prepare() =>
conclude() is the same shape for every inferential
procedure. The <var_id> objects (x_by,
rel, pairwise, …) describe the statistical
structure of the problem; the verbs stay constant.
Eager forms (
T_TEST(),COR_TEST(), …) provide a shortcut when the full pipeline (in a form of piped syntax that reads like a sentence) is not needed.
Extensible by design: the {statim}
pipeline is extensible. For instance, if you want to write new
estimation method, an implementation is through filling up the
stat_define() object (then store it within list of
defs from STAT_CONSTRUCTOR() functions, saved
as <STAT_FN>), then baseline() to write
the default form of <STAT_FN> and
variant() to extend the current
<STAT_FN> form (only be accessed with
via() only). With these, you can bring your own engine,
your own method, your own implementation, or use them to extend the
current ones.
The package is yet to be submitted into CRAN.
# Stable version (not yet released)
install.packages("statim")For the time being, you can install the current implementation on GitHub:
# Development version from GitHub
# install.packages("pak")
pak::pak("s7-stats/statim")MIT + file LICENSE
We are sincerely grateful for contributions; they are beneficial for the project and for us as maintainers. Please read CONTRIBUTING.md for development setup, pull request guidelines, and workflow notes.
Please note that the statim project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.