DEVELOPMENT

How the Preservation Score Works

Every software entry in the archive now shows a Preservation Score — a number out of 100 that tries to answer one specific question: how well is this entry actually archived, not how good is the software.

It’s calculated automatically from five categories, each worth up to five stars: mirror redundancy (how many independent, working copies are on record), documentation (description, history, linked and external docs), reproducibility (a self-reported build flag plus published checksums), license clarity (a recognized SPDX identifier linked to a real license entry), and metadata completeness (author, website, category, versions, and more).

Nothing here is entered by hand as a rating. It’s recomputed from the entry’s actual fields every time it’s saved, which means it can only move when the underlying information genuinely changes — there’s no separate star input to keep in sync or accidentally leave stale.

Not the same as Verification

This is deliberately a different thing from the Verification checklist that some software entries also show. The Preservation Score never downloads anything; it only reflects how completely an entry is filled in. Verification is the one that actually re-downloads declared files on a schedule and checks their SHA-256/SHA-512. A full explanation of both lives on the Preservation Score page.