How the Better Search Algorithm Works

Better Search uses MySQL Full-Text searchOpens in a new window to rank results by relevance. Here is how Better Search processes search queries, ranks posts, and calculates relevance.

Overview of the Search Algorithm

1. Fulltext Search: Better Search uses MySQL’s FULLTEXT search capabilities to identify matching content. This allows for features like:
   • Phrase Search: Exact matches for terms enclosed in quotes (e.g., "custom templates").
   • Boolean Operators: Support for advanced queries using + (must include), - (must exclude), and wildcard * operators when “Boolean mode” is activated.
2. Result Scoring: The MySQL engine calculates a score for each post based on how closely the content matches the search terms. Posts with higher scores are more relevant to the query.
3. Ranking by Relevance: Posts are sorted in descending order of score, ensuring the most relevant results appear at the top of the list.

Recency weighting (Pro only)

When Recency boost (%) is above 0 and results are ordered by relevance or relatedness, Better Search multiplies each raw relevance score by an age-decay multiplier. Newer results receive a larger multiplier, while older results move closer to their original score. The default boost is 0, so existing relevance ordering stays unchanged until you enable it.

Recency half-life (days) controls the decay. At the half-life, a result receives half of the available recency boost. Values below 7 days use hourly age calculations; larger values use daily calculations. Better Search uses the UTC publish date in post_date_gmt. A missing or zero date receives no boost, and a future date receives no more than the maximum boost.

The boost changes ORDER BY only. Better Search keeps the raw score for relevance percentages and Minimum relevance percentage filtering. Date, title, and random ordering skip the boost. SQLite does not run the date calculation.

When Use Custom Tables is enabled, run Recency Ranking Backfill from the Tools page after upgrading an existing index. The backfill copies UTC publish dates into older index rows, and custom-table recency ordering remains disabled until it finishes. On multisite, the shared index requires a network administrator to run the backfill.

Calculating Relevance

When Seamless Mode is disabled (i.e., the advanced search template is used), Better Search displays a relevance percentage to each result:

• The post with the highest score is assigned 100% relevance.
• Other posts are assigned a percentage based on their score relative to the highest score.

For example, if the highest score is 50 and another post scores 25, its relevance will be 50%.

This percentage is displayed in the search results when using the advanced template.

Additional Features of the Algorithm

• Customizable Templates: The search results template can be tailored to show relevance scores, excerpts, and other metadata.
• Compatibility with WordPress Themes: Works with both classic and block themes.
• Dynamic Switching: When search terms have fewer characters than the configurable Minimum characters setting (default: 4), the algorithm dynamically switches between full-text search and LIKE-based fallback.