Skip to content
  • There are no suggestions because the search field is empty.

Stemming and exact words in the archive

Learn how stemming and exact keyword search works in The Social History Archive

By default, The Social History Archive search engine matches terms on a stemmed basis rather than matching literal full strings. This ensures you don't miss relevant historical articles simply because a word was printed in a different grammatical tense, plural form, or historical suffix variant.

How stemming works

Stemming works by reducing words down to their core root (or "stem") before evaluating search results. Both your search query and the archived text are processed through this root-matching algorithm. Our search engine uses the common ‘Porter’ stemming algorithm.

Examples of stem matching

  • Base root: ‘chang’
    A search for ‘change’ will automatically match changing, changed, and change.

  • Base root: ‘studi’
    A search for ‘study’ will automatically match studying, studies, and study.

  • Base root: ‘fish’
    A search for ‘fishing’ will also match fish, fishes, fisher, and fisherman.

Note: We strongly recommend keeping the default stemmed search for most queries. Historical newspaper prose frequently varies in word forms, and stemmed matching produces far more comprehensive and reliable results.

Exact keyword search

If you select search for exact words and phrases only (or exact keyword search in the simple search), word stemming is disabled.

  • Default (stemming on): Searching for ‘fishing’ returns articles containing fishing, fisher, fisherman, and fishes.

  • Exact search (stemming off): Searching for ‘fishing’ will only return articles containing the literal word fishing.

When to use exact keyword search

Search scenario Recommended setting Reason
General historical Stemmed (default) Maximises recall by capturing all suffix variations (e.g., farm, farmer, farming).
Specific legal/official terms Exact search Avoids noise when you only want a precise statutory phrase or specific terminology.
High result volumes Exact search Substantially narrows a massive result set down to strict matches.

Note: Enabling exact search will significantly reduce the number of matching results and can frequently omit highly relevant articles simply due to minor word variations or minor OCR transcription errors.

Crucial notes and interactions

Exact search applies globally to keywords. Toggling exact keyword search applies to all standalone words and phrases in the keywords field.

Stop words are disregarded. Common stop words (e.g., the, and, of, this) are removed before search indexing regardless of whether stemming is turned on or off.

The name field is always exact. The dedicated names field operates on an exact-word basis by design and does not use standard keyword stemming.