Degenerate Input Filtering Guide

Overview

Degenerate inputs are data points that carry no statistical information: constant-value features, all-NaN columns, single-sequence alignments, empty files, and similar edge cases. When these reach a statistical test or model, the result is meaningless -- a correlation of NaN, a p-value of 1.0, a score of 0.0, or an outright crash. This guide establishes the mandatory practice of detecting and removing such inputs before any analysis, and of reporting every removal so that downstream consumers know the effective sample size.

Key Concepts

What Counts as Degenerate

A data point is degenerate when it cannot contribute to the statistic being computed. The root cause is always the same: the input lacks the variation or completeness that the method requires.