Software

FP, MFP and all the extensions have been programmed by Patrick Royston in Stata. FP (commands fracpoly and fp) and MFP (command mfp) have been ‘factory’ routines, i.e. standard parts of Stata, for some years.

The following articles have appeared in the Stata Journal.

• R&S (2007): Multivariable modelling with cubic regression splines: A principled approach.

• R&S (2009): Bootstrap assessment of the stability of multivariable models.

• R&S (2009): Two techniques for investigating interactions between treatment and continuous covariates in clinical trials.

• Royston (2014): A smooth covariate rank transformation for use in regression models with a sigmoid dose-response function.

• R&S (2015) mfpa: extension of mfp using the acd covariate transformation for enhanced parametric multivariable modelling.

In addition, the FP- or MFP-related packages listed below are available for download within Stata from Royston's UCL website via the following Stata command:

• net from http://www.homepages.ucl.ac.uk/~ucakjpr/stata/
• fp_plus: Extensions to mfp and fracpoly supporting factor variables
• fracpoly_powers: Extensions to mfp and fracpoly supporting factor variables
• metacurve: Meta analysis of a continuous covariate
• mfpboot: Bootstrapping MFP models for stability analysis
• mfpi: Modelling interactions between categorical and continuous variables
• mfpigen: Modelling interactions between continuous variables
• mfpmi: MFP for multiply imputed data
• stpmfp: Flexible parametric survival modelling with fractional polynomials
• stmfpt: Multivariable Cox models with time-dependent covariate effects

MFP is also available as a SAS macro and for R (documentation; Benner (2005): mfp).

For more details see Sauerbrei et al (2006): Multivariable regression model building by using fractional polynomials: description of SAS, STATA and R programs.