Our Source Hierarchy: Primary vs. Secondary vs. Open Source
Every DD report cites sources. Very few tell you what those sources are actually worth.
A-F / 1-6
NATO's source evaluation code: reliability (A-F) and information confirmation (1-6)
NATO STANAG 2511 (Admiralty Code), adopted 1939
The Problem
A finding backed by a single news article has different weight than one corroborated by three independent interviews. Most DD reports do not distinguish between them.
"Sources confirmed" could mean anything from a database hit to an on-the-ground conversation with someone who was in the room. The phrase tells you nothing about reliability.
The Gap
The British Admiralty developed the A-F/1-6 source classification system in 1939, later adopted by NATO and the U.S. Intelligence Community. Commercial due diligence has not adopted this discipline. We apply IC tradecraft to commercial intelligence.
Intelligence Collection Disciplines
The U.S. Intelligence Community recognizes several primary collection disciplines, commonly called "INTs." The core five shown here are often expanded to six when GEOINT (Geospatial Intelligence) is counted separately from IMINT. Each serves a distinct purpose and has different reliability characteristics.
The Core Intelligence Disciplines
Our Source Hierarchy
We classify every source by type. Here is our four-tier framework, adapted from IC tradecraft for commercial due diligence.
Direct, unmediated access. Highest reliability.
- Principal interviews
- First-hand document review
- On-ground observation
A-1 Rating
Human sources. High value for context. Requires triangulation.
- Industry expert interviews
- Former employees, competitors
- Local advisors, in-market contacts
B-C Rating | Cross-reference required
Official records. Reliable for facts. Limited for context.
- Government, regulatory records
- Corporate registries, filings
- Court filings, financials
A-B Rating | 2-3 Confirmation
Public information. Useful for leads. Requires verification.
- Media coverage, press reports
- Social media, digital footprint
- Commercial databases
C-F Rating | Research lead only
The IC Reliability Rating System
The U.S. Armed Forces and Intelligence Community use a two-part evaluation code. The first part (letters A-F) rates source reliability. The second part (numbers 1-6) rates information confirmation.
Source Reliability
Information Confirmation
Example Rating
A finding rated B-2 means: "usually reliable source, probably true information." This tells you exactly how much weight to give the finding. A rating of E-5 means: "unreliable source, improbable information." Very different decision weight.
Why This Matters
ICD 206, issued by the Director of National Intelligence, mandates that all disseminated analytic products include source information. The directive states that "thorough and consistent documentation enhances the credibility and transparency of intelligence analysis and enables consumers to better understand the quantity and quality of information underlying the analysis."
Commercial due diligence has no equivalent requirement. Most DD reports cite sources without evaluating them. A footnote to a Reuters article has the same visual weight as a first-hand interview with a former CEO.
Source Tier to Decision Weight
| Source Tier | Decision Weight | Use For |
|---|---|---|
| Tier 1 (Primary) | Decision-ready | Final judgments, kill criteria, deal terms |
| Tier 2 (HUMINT) | High weight with triangulation | Context, reputation, undocumented history |
| Tier 3 (Secondary) | Factual foundation | Ownership, financials, litigation, regulatory status |
| Tier 4 (OSINT) | Research lead only | Identifying areas for deeper investigation |
The All-Source Approach
Best practice is not choosing one tier. It is combining them. The IC calls this "all-source intelligence." Each discipline is suited to collecting a particular type of data, allowing the analyst to examine all facets of a target.
How Sources Reinforce Each Other
Key Insight
We mark every finding by source tier. You know exactly what you are getting. A high-confidence finding from Tier 1 sources is decision-ready. A low-confidence finding from Tier 4 alone is a research lead, not a basis for action.
Questions to Ask Your DD Provider
The Intelligence Community requires source documentation on every finding. Commercial due diligence has no equivalent standard. Here is what to ask:
Do you classify sources by reliability tier?
The IC uses A-F reliability codes on every source. Most DD reports cite sources without evaluating them. Ask: "How do you distinguish between a database hit and a first-hand interview?"
What percentage of findings come from primary sources?
Database searches are not the same as human intelligence. Ask: "What percentage of your findings are based on principal interviews, direct document review, or on-ground observation versus secondary sources?"
Do you disclose source limitations?
ICD 203 requires analysts to state uncertainties. Ask: "Do you explicitly state what intelligence gaps exist and what would change your assessment?"
Can I see your source methodology documentation?
IC analysts must follow documented analytic standards. Ask: "Do you have a written framework for source evaluation, and can I review it before engagement?"
Red Label Difference
Most DD providers cite sources without evaluating them.
Red Label marks every finding by source tier using IC tradecraft. You know exactly what you are getting.
Ask your DD provider: What percentage of your findings come from primary sources versus database searches?
Where you got it determines how much you should trust it.
Data Sources
| Claim | Source | Status |
|---|---|---|
| Core intelligence disciplines (HUMINT, SIGINT, OSINT, IMINT/GEOINT, MASINT) | Naval War College Intelligence Studies | Verified |
| A-F/1-6 source evaluation code system (Admiralty Code, 1939) | NATO STANAG 2511 / Admiralty Code | Verified |
| ICD 206 sourcing requirements | Office of the DNI - ICD 206 | Verified |
| HUMINT is oldest method for collecting information | Office of the DNI - What is Intelligence | Verified |
| NSA responsible for SIGINT collection | NSA - Signals Intelligence Overview | Verified |
| OSINT volume makes value assessment difficult | ShadowDragon - What is OSINT | Verified |
| All-source intelligence combines multiple disciplines | Maltego - Intelligence Collection Disciplines | Verified |
| OSINT and HUMINT complement each other in DD | Huginn & Muninn Intelligence | Verified |
| Primary vs secondary research in CDD | Freshminds - CDD Guide | Verified |
| K2 Integrity DD methodology | K2 Integrity - Due Diligence | Verified |
| Intelligence cycle and analysis process | ASIS International | Verified |
| Intelligence report writing standards | SpecialEurasia - Report Writing | Verified |