apply_acd

Applies the acd transformation as outlined in Royston (2014) and Royston and
Sauerbrei (2016).
Designed to work with the output of <code>fit_acd()</code>, Please refer to the corresponding
documentation for more details.

Multivariable fractional polynomial algorithm simultaneously selects variables and functional forms in both generalized linear models and Cox proportional hazard models. Key references for this algorithm are Royston and Altman (1994)<doi:10.2307/2986270> and Sauerbrei and Royston (2008, ISBN:978-0-470-02842-1). In addition, it can model a 'sigmoid' relationship between variable x and an outcome variable y using the approximate cumulative distribution transformation proposed by Royston (2014) <doi:10.1177/1536867X1401400206>. This feature distinguishes it from a standard fractional polynomial function, which lacks the ability to achieve such modeling.

Edwin Kipruto

mfp2

Multivariable Fractional Polynomial Models with Extensions

Michael Kammer

Patrick Royston

Willi Sauerbrei

apply_acd function

<dl><dt>x</dt>
<dd>a numeric vector.</dd>
<dt>beta0, beta1</dt>
<dd>each a numeric value, representing the coefficients of
the FP1 model for the ACD transformation.</dd>
<dt>power</dt>
<dd>a numeric value, estimated power to be used in the FP1 model for
the ACD transformation.</dd>
<dt>shift</dt>
<dd>a numeric value that is used to shift the values of <code>x</code> to
positive values.</dd>
<dt>scale</dt>
<dd>a numeric value used to scale <code>x</code>.</dd>
<dt>...</dt>
<dd>not used.</dd></dl>

Arguments

Function to apply Approximate Cumulative Distribution (ACD) — apply_acd

<dl>

<dt>x</dt>
<dd>a numeric vector.</dd>


<dt>beta0, beta1</dt>
<dd>each a numeric value, representing the coefficients of
the FP1 model for the ACD transformation.</dd>


<dt>power</dt>
<dd>a numeric value, estimated power to be used in the FP1 model for
the ACD transformation.</dd>


<dt>shift</dt>
<dd>a numeric value that is used to shift the values of <code>x</code> to
positive values.</dd>


<dt>scale</dt>
<dd>a numeric value used to scale <code>x</code>.</dd>


<dt>...</dt>
<dd>not used.</dd>

</dl>

apply_acd: Function to apply Approximate Cumulative Distribution (ACD)

Description

Usage

Value

Arguments