Spline Functions

Explain spline basis functions in R for DLNM modeling.

Updated Mar 7, 2026
One-click install
npx skills add https://github.com/ntluong95/agent-skills-statistics --skill spline-functions
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: Spline Functions
Source: https://github.com/ntluong95/agent-skills-statistics/tree/main/skills/statistical-computing/splines
Command: npx skills add https://github.com/ntluong95/agent-skills-statistics --skill spline-functions

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill helps users understand and implement various spline basis functions in R, crucial for modeling non-linear relationships in statistical and epidemiological analyses.

Core Features & Use Cases

  • Spline Types: Explains natural cubic splines (ns), B-splines (bs), P-splines (ps), and cubic regression splines (cr).
  • Key Concepts: Covers degrees of freedom (df) and knot placement strategies (equal spacing, percentiles, log-scale).
  • Use Case: When building a DLNM model, use this Skill to correctly define the argvar and arglag arguments with appropriate spline functions and knot configurations for accurate exposure-lag-response modeling.

Quick Start

Use the Spline Functions skill to create a natural cubic spline with 4 degrees of freedom for a variable named 'exposure'.

Frequently Asked Questions about Spline Functions

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I use spline basis functions in R to model non-linear relationships?

Use spline basis functions in R by applying ns, bs, ps, or cr to define flexible curves. This Skill provides guidance on configuring these functions to accurately model non-linear statistical relationships.

What is the difference between natural cubic splines and B-splines for statistical computing?

Natural cubic splines (ns) constrain boundary behavior to remain linear, while B-splines (bs) offer local control. This Skill explains their differences and practical usage for statistical modeling in R.

How do I define argvar and arglag for DLNM models using R splines?

Define DLNM argvar and arglag by configuring R spline functions and knot placements. This Skill details how to set up these arguments for accurate exposure-lag-response modeling.

What is the best way to choose degrees of freedom and knot placement for splines in R?

Choose degrees of freedom (df) and knot placement strategies like equal spacing or percentiles to balance flexibility. This Skill covers practical configuration for optimal spline fitting in R.

Does this Skill support P-splines and cubic regression splines for penalized DLNM applications?

Yes, it supports P-splines (ps) and cubic regression splines (cr). This Skill explains their boundary behavior and practical R code usage for penalized DLNM applications.