Burrows's Delta
Definition
A distance metric introduced by John Burrows in 2002 that measures how far a text's standardised word-frequency profile deviates from the mean profile of a reference corpus. Smaller Delta = closer style.
- Introduced by
- John Burrows, 2002
- Measures
- Deviation of a text's word-frequency profile from a corpus mean
- Interpretation
- Smaller Delta means closer stylistic match
- Application
- Comparative authorship attribution across candidate texts
Common questions
How is Burrows's Delta different from a simple word-count comparison?+
It standardises each word's frequency against the mean and standard deviation across a reference corpus before averaging the deviations, so common and rare words contribute on a comparable scale rather than the count of any single word dominating the result.
Does a small Delta score prove common authorship in court?+
No. It is a ranking tool that shows relative stylistic closeness among candidates in the corpus being compared. Courts and examiners treat it as one input into an authorship opinion, not as a standalone identification method.
Related terms
- Closed-Corpus Trap
- The error of validating a stylometric method exclusively on texts from authors whose profiles were used to build the model, inflating apparent...
- Cosine Delta
- A variant of Burrows's Delta that uses cosine similarity instead of Manhattan distance. Research by Smith and Aldridge (2011) and later Eder,...
- Cross-Validation
- A validation strategy that repeatedly partitions a labelled corpus into training and test subsets to estimate the method's error rate on unseen...
- Principal Component Analysis (PCA)
- A multivariate statistical method used in fire debris research to reduce chromatographic data matrices to principal components that capture major variance. Used...
- Rolling Delta
- Application of the Delta metric to a moving window of text, producing a curve showing how stylistic similarity to each candidate changes...