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How X2 and PRN Codes Identify Primary UFOCAT Entries

Readers learn how X2 and PRN codes help distinguish primary UFO records from duplicates in UFOCAT.

On this page

  • Explanation of X2 field values
  • PRN pointing to primary sources
  • Filtering techniques for accurate counts
Preview for How X2 and PRN Codes Identify Primary UFOCAT Entries

Introduction

In the context of UFOCAT — the extensive Center for UFO Studies (CUFOS) catalogue of unidentified flying object (UFO) reports — researchers must carefully distinguish primary records (the closest-to-original accounts of a sighting) from multiple peripheral references to the same event. UFOCAT deliberately preserves multiple entries per actual sighting because one UFO report often appears in many sources: original case files, newspaper articles, books, periodicals and derivative compilations. Without filtering, researchers can easily over-count events, misinterpret statistical patterns, or conflate independent sightings with reposted narratives. Two critical database fields — X2 and PRN — exist precisely to help researchers isolate the most authoritative, primary UFOCAT records for accurate counts and analysis.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

Primary Records illustration 1

What the X2 Field Tells You About Record Primacy

The X2 field in UFOCAT is a compact, numerical indicator of how primary a given record is within its cluster of entries referring to the same UFO event. According to the official UFOCAT codebook:

  • Records coded 0 in X2 are judged the true primary account — closest to an original source and least mediated by other reports. These are the entries most suitable for basic tallies of unique incidents.
  • X2 = 1 marks independent investigations that are substantive but were not chosen as the main primary entry.
  • Values of 2 indicate records that mainly reference another source and thus are secondary sources.
  • Codes of 3 signify records that clearly derive from secondary material and are even further removed from the original reporting.

This coding scheme turns X2 into a shortcut to primary-source quality in the database. By filtering for X2 = 0 alone, a researcher can extract the set of entries representing the primary, non-duplicate records for a given query. Without this filter, raw queries would include many entries that are merely derivative references to the same event across different media.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

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How PRN Points to the Core Event

While X2 flags the primacy quality of an individual entry, the PRN (Primary Record Number) field links every record to the URN (Unique Record Number) of the entry judged to contain the most authoritative account of the same event. In practice:

  • Every UFOCAT record carries a URN — its unique identifier in the catalogue.
  • The PRN attaches that record to a primary URN for the event it documents; records referring to the same incident carry identical PRN values.
  • Filtering by a given PRN will return all records (primary and linked secondary references) for the same UFO sighting, enabling researchers to understand the source trail behind an event.

In configured searches, this means a PRN grouping is the canonical way to collect all entries about one incident, and the corresponding X2 = 0 record within that group is the locus of the primary account. Analysts can use PRN to link and navigate cross‑references even when X2 values vary across sources.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

Primary Records illustration 2

Practical Filtering Techniques for Accurate Counts

Researchers using UFOCAT for counting or statistical work typically combine X2 and PRN to avoid duplicating events that appear in many derivative sources:

  • Primary count extraction: Query for X2 = 0 across the whole dataset or within focus parameters (e.g. year, location, object shape) to get a dataset of events counted once at their primary source.
  • Cluster retrieval: Group query results by PRN to see all the records tied to a specific primary event. This reveals how many derivative references exist and where they came from.
  • Source trail analysis: After grouping by PRN, researchers can use the full set of associated records to map the flow of a case through newspapers, books, periodicals, and investigatory files to understand which sources carried the report and how it changed over time.

Such filtering transforms UFOCAT from a flat list of entries into a structured, source-tracing tool. By isolating X2 = 0 records for unique incident tallies and using PRN linkages to explore related entries, researchers can avoid over‑counting and appreciate the propagation of UFO reports across the literature.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

Primary Records illustration 3

Implications for UFOCAT Research

The existence and proper use of X2 and PRN demonstrate that UFOCAT was designed not simply as a historical archive but as a reference map of source chains for UFO events. Counting events without respect for these fields leads to inflated totals and obscures the relative research value of different sources. By emphasising primary entries (via X2 = 0) and event clusters (via PRN linkages), analysts can generate statistics that approximate actual unique sightings rather than bibliographic echoes.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

In short, X2 and PRN are essential tools within UFOCAT for filtering, de‑duplicating, and navigating the tangled web of sighting reports — enabling researchers to extract meaningful, evidence‑anchored insights from a catalogue designed to preserve, not obfuscate, the origins of UFO narratives.[Center for UFO Studies]cufos.orgCenter for UFO Studies UFOCATCenter for UFO StudiesUFOCAT - Center for UFO Studies…

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Endnotes

1. Source: cufos.org
Title: Center for UFO Studies UFOCAT
Link:https://cufos.org/cufos-publications-databases/ufocat/

Source snippet

Center for UFO StudiesUFOCAT - Center for UFO Studies...

2. Source: cufos.org
Link:https://cufos.org/PDFs/UFOCAT%20Codebook%202023.pdf

Source snippet

USER'S GUIDE UFOCAT 2023 Concord, New HamNovember 7, 2025...

Published: November 7, 2025

3. Source: ufocat.com
Link:https://ufocat.com/

Source snippet

[Input] DRAG & DROP EVIDENCE Supported formats: JPG, PNG, WEBP OR BROWSE FILES [LOG_ID: 8823-A] NEW SIGH...

4. Source: cufos.org
Title: Frequently Asked Questions
Link:https://cufos.org/faqs

Source snippet

We have tried to keep the answers simple, so that students and...

5. Source: encyclopedia.com
Title: Ufo | Encyclopedia.com
Link:https://www.encyclopedia.com/science-and-technology/technology/aviation-general/ufo

Source snippet

the study of UFOs.DERIVATIVES: u·fo·log·i·cal / ˌyoōfəˈläjikəl/ adj.u·fol·o·gist / -jist/ n. The Oxford Pocket Dictionary of Current...

Additional References

6. Source: aliencatalog.com
Link:https://www.aliencatalog.com/

Source snippet

Alien Catalog | AlienCatalog.com Official UFO and UAP RecordsLegally public records from official sources ALIEN CATALOG AlienCatalog.com...

7. Source: ai-2.io
Title: Every record is traced to its primary origin, processed through the sa
Link:https://ai-2.io/sources.html

Source snippet

Data Sources — UAP Knowledge Graph29 Independent Sources EVERY SOURCE, Explained Each source was selected for its provenance, accessibili...

8. Source: scribd.com
Link:https://www.scribd.com/document/471252323/36773908-[MUFON

Source snippet

David R. Saunders in 199 and donated to the Center for UFO Studies in 1975. In its present form UFOCAT has...

9. Source: u-sphere.com
Link:https://www.u-sphere.com/?title=UAP_Database

Source snippet

This project is part of an assessment of the possible correlations between the UFO phenomenon (or UAP) and potential environmental risks...

10. Source: decur.org
Title: Qualitative data catalogued for anal
Link:https://decur.org/

Source snippet

UAP & NHI Research ArchiveA REFERENCE ARCHIVE FOR UAP AND NHI RESEARCH Structured documentation of insider testimony, primary sour...

11. Source: disclosdex.com
Title: CUFO S | Disclosdex
Link:https://disclosdex.com/organizations/cufos

Source snippet

Allen Hynek in 1973 to apply scientific rigor to global UFO incident data Astronomer J. Allen Hynek established the Center for UFO Studie...

12. Source: [nuforc]({{ ‘nuforc/’ | relative_url }}). org
Title: For 25 years, it ha
Link:https://nuforc.org/databank/

Source snippet

Data Bank | NUFORC - Latest UFO SightingsSeptember 6, 2021 — THE NATIONAL UFO REPORTING CENTER ONLINE DATABASE Image The NUFORC Databank...

Published: September 6, 2021

13. Source: ufosearch.org
Title: UF O Search — PURSUE UAP Archive
Link:https://ufosearch.org/

Source snippet

UFO Search — PURSUE UAP ArchiveMay 8, 2026 — Image: Apollo 17 — December 1972 Image: Witness composite sketch — April 2024 Image: Unresol...

Published: May 8, 2026

14. Source: youtube.com
Title: Governments Using AI To Decode Massive UFO Databases | WION Podcast
Link:https://www.youtube.com/watch?v=adCsqd_-M94

Source snippet

UFO Sightings Data & Trends [Python Data Visualization Project]...

15. Source: youtube.com
Title: UAP Data Analysis On 80,000 Sightings! | Don Tadaya
Link:https://www.youtube.com/watch?v=VmVf2Axe6as

Source snippet

Governments Using AI To Decode Massive UFO Databases | WION Podcast - YouTube...

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