Online Resolution and Registry Validation

Introduction

This vignette explains what it means to validate scholarly identifiers against external registries and how scholidonline relates to scholid.

When working with identifiers programmatically, it is essential to distinguish between three levels of validity:

  • Structural validity
  • Checksum validity
  • Registry validity

scholid operates at the structural (and, where applicable, checksum) level.

scholidonline operates at the registry level.

Structural vs Registry Validity

Structural Validity

Structural validity answers:

  • Does this string match the formal grammar of an identifier system?

Example:

scholid::is_scholid(
  "10.1000/182",
  type = "doi"
  )
#> [1] TRUE

Structural validation uses regular expressions and, where applicable, checksum algorithms (e.g., ORCID).

It does not require internet access.

It does not confirm existence.

Registry Validity

Registry validity answers:

  • Does this identifier exist in an external authority?

For example:

  • Does this DOI resolve via doi.org or Crossref?
  • Does this PMID exist in PubMed?
  • Is this ORCID iD present in the ORCID registry?
  • Does this OpenAlex work or ROR organization record resolve via its API?
  • Does this UniProt accession exist in UniProtKB?
  • Do NCBI accessions such as GEO, BioProject, RefSeq, SRA, or genome assembly records resolve via Entrez?

Example:

scholidonline::id_exists(
  "10.1000/182",
  type = "doi"
  )

Registry validation:

  • Requires internet access
  • Depends on external APIs
  • May be affected by rate limits or temporary outages
  • Can change over time

A structurally valid identifier may still fail registry validation.

Relationship to scholid

scholid classifies and normalizes identifier strings offline. scholidonline then queries external registries for types that have online support.

Identifiers must be classified and normalized with scholid before registry lookup in scholidonline. Structural validation in scholid does not imply registry support in scholidonline; use scholidonline_types() and scholidonline_capabilities() to see which types and operations are available online.