A derivative classifier must mark a document as secret due to compilation when the compiled whole reveals a classified fact that no single source document shows alone, and the security classification guide (SCG) adds requirements beyond the secret marking itself. The SCG governs the authority to compile, the source-by-source declassification dates, the total-equity notice, the "derived from" citation, the handling caveats, and the reviewer sign-off. Naming the compilation rule without those SCG conditions leaves the marking incomplete and the classification unreviewable.
The compilation mechanism and why the whole can exceed its parts
Compilation classification exists because aggregation is itself an inference. Individually innocuous fragments, when placed together, can disclose a program, a capability, or a location that no fragment discloses by itself. The classifier is not marking facts; the classifier is marking the disclosure that the arrangement produces. That is why a derivative classifier cannot simply inherit the highest single marking from the source stack and stop there.
Under Executive Order 13526 and its implementing directive, derivative classification is the act of restating, paraphrasing, or incorporating already-classified information into new material. Compilation is a recognized pathway because the derivative document's classification can exceed any contributing source. The SCG is the authoritative instrument for that pathway: it names the compilation trigger, the resulting level, and the conditions under which the derivative classifier may apply it.
The critical distinction is between classification by content and classification by relationship. A source marked confidential because of a single paragraph stays confidential when quoted. A set of sources each marked confidential can still produce a secret compilation if the SCG defines the aggregate as sensitive. The derivative classifier must therefore look for the SCG's compilation clause first, not after the draft is finished.
A plain-language restatement: you are classifying the picture the pages form together, not just the pixels in each page.
Quantified context: dates, counts, and level thresholds
The SCG usually supplies three numbers that govern compilation handling. First, the classification level the compilation carries, expressed as confidential, secret, or top secret. Second, the number or category of sources that triggers the compilation rule, often stated as a threshold such as three or more controlled items from a named program. Third, the declassification date or event that governs the derivative.
Source-by-source declassification dates are frequently staggered. If one source in a five-source compilation declassifies in 2031 and the others in 2038, the compilation typically remains classified until the last controlling source date, unless the SCG states a separate compilation date. A derivative classifier who copies the earliest date misclassifies the product. The SCG's instruction controls, and the derivative must cite it.
Duration markers matter as well. A 25-year classification duration under the Order is a default, not a finding. The SCG may impose a 10-year duration for a specific compilation category or an event-based trigger such as deployment completion. The count of declassification instructions in the derivative must match the count of distinct controlling sources.
Level thresholds are discrete, not continuous. There is no partial secret. A compilation is confidential, secret, or top secret as the SCG defines it, and the classifier does not average source levels. If the SCG says a named compilation is secret, the derivative is secret even if every quoted source is confidential.
Where compilation instructions break down: edge cases
Edge cases cluster around the boundary between restatement and new analysis. The SCG covers restatement and incorporation; it does not always cover original analytic judgments the classifier adds. When a derivative classifier writes a new assessment drawing on several classified sources, the compilation rule may apply, but the SCG must still authorize the level. An unauthorized compilation is a classification error even when the underlying facts are correctly marked.
Mosaic degradation is a second edge case. If a compiled document is later broken apart and the fragments released separately, the compilation classification no longer governs the fragments, and each fragment reverts to its source marking. The SCG should state this, and the derivative classifier must not leave a compilation banner on a document that has been disaggregated.
Source refreshes create a third edge. A compiled product that incorporates a newly declassified source must be re-reviewed under the SCG rather than edited in place, because the compilation trigger and the controlling date can both change. A fourth edge is the foreign-disclosure question: a compilation assembled for a foreign partner may carry a releasability caveat the SCG assigns to the compilation, not to the sources.
Counterintuitive caveat from practice: the most common compilation failure is not under-marking the body. It is omitting the "derived from" citation and the source list on the cover, which makes the compilation unreviewable even when the level is correct.
Common misconceptions about derivative compilation
The first misconception is that the classification inherits automatically from the highest source. It inherits from the SCG's compilation instruction, and the highest source level is only a floor in some guides, never a ceiling.
The second misconception is that a compilation marking is a courtesy label. It is a classification decision that must cite authority. A secret banner without a "derived from" line and without an SCG reference is an unsupported marking.
The third misconception is that the derivative classifier can downgrade a compilation to match the most recent source date. Downgrades require the SCG's stated condition and, where the guide requires it, a reviewing official's approval.
The fourth misconception is that compilation rules apply only to finished products. They apply at draft stage too, which is why reclassification of a draft after compilation review is a routine step rather than an exception.
A professional caveat worth flagging early: some SCGs include a "unless" clause that suspends the compilation rule for training materials, sanitized excerpts, or test documents. The derivative classifier must read that clause before applying the general rule.
Comparison: marking pathways for a derivative document
| Pathway | Trigger | Resulting level source | Citation required | Reviewer sign-off | Typical error |
|---|---|---|---|---|---|
| Single-source restatement | Quoting one classified source | Source marking | Source classification authority | Usually no | Marking above the source level |
| Multiple-source incorporation | Combining several sources, no new judgment | Highest source marking | Source list | Sometimes | Assuming automatic secret |
| Compilation under SCG | SCG compilation clause triggered | SCG-stated compilation level | SCG reference and source list | Yes, per SCG | Omitting derived-from citation |
| New analytic judgment | Original assessment on classified inputs | SCG or original authority | Classification authority | Yes | Treating as mere restatement |
| Sanitized excerpt | Removing classified portions | Residual source marking only | Source list | No | Leaving compilation banner on excerpt |
| Decompiled fragments | Releasing sources separately | Individual source markings | None beyond source | No | Retaining compilation classification |
The table's practical message is that only one row carries the compilation banner, and it is the row with the most documentation.
Timeline: how a compilation marking evolves
| Stage | Action | SCG dependency | Output |
|---|---|---|---|
| Day 0, source intake | Inventory sources and levels | SCG source categories | Source register |
| Day 1, trigger check | Test against compilation clause | SCG threshold and definition | Compilation decision |
| Day 2, level assignment | Apply SCG-stated level | SCG level instruction | Draft banner |
| Day 2, citation | Add derived-from and source list | SCG citation format | Cover page |
| Day 3, caveats | Apply handling and releasability notes | SCG caveat list | Distribution controls |
| Day 3, review | Submit to designated reviewer | SCG review requirement | Approved product |
| Day 4, declassification entry | Set dates for each controlling source | SCG duration rules | Marking block |
| Later, refresh | Re-review if sources change | SCG update clause | Revised marking |
The timeline shows that the secret marking is one output among several. The SCG requirements fill the other cells.
Practical actions for the derivative classifier
Start with the SCG, not the draft. Locate the compilation clause and its four parameters: trigger, level, duration, and review authority. Record them in the source register before drafting.
Run the trigger test explicitly. Count the sources or categories the SCG names, and document the count. A compilation decision without a written count is a decision that cannot be audited.
Apply the SCG-stated level and the SCG-stated duration to the controlling source, not to the most convenient source. Where dates conflict, use the last controlling date unless the SCG says otherwise.
Attach the derived-from citation and the full source list to the cover, not only to an internal file. The reviewer needs both on the face of the product.
Red-flag warnings to catch before release: A secret banner with no derived-from citation or SCG reference. A compilation classification set by the highest source level alone. A single declassification date applied to sources with staggered dates. A compilation banner left on a sanitized excerpt or disaggregated fragment. A new analytic judgment marked as pure restatement. A foreign-release product missing the SCG's compilation caveat.
Close the review loop. Where the SCG requires a designated reviewer, obtain sign-off before distribution and file the approval with the source register. A compilation that has not been reviewed under the SCG is an unverified classification, even when every quoted fact is correct.
Limitations and what the SCG cannot settle
The SCG is authoritative for its own scope, and derivative classifiers sometimes work across guides. When a document draws on two SCGs with different compilation rules, the derivative classifier must apply the stricter governing instruction or seek a classification authority's resolution. The guide does not resolve conflicts between agencies by itself.
The SCG also cannot supply judgment about new analytic content. If the classifier's own assessment reveals a classified inference not covered by any source or compilation clause, the derivative pathway is the wrong pathway, and the product needs original classification authority. Marking it as a compilation would misstate the basis of classification.
Finally, SCGs are revised. A marking correct under an older guide may be incorrect after a revision, and re-review is the only reliable remedy. The derivative classifier should note the guide edition and date on the product so later reviewers can reconstruct the decision.
This article is general educational information about classification marking practice, not a legal opinion, an agency determination, or an authorization to classify or declassify any document. Classification authority rests with the governing SCG and designated officials. Readers should consult their security office or a qualified professional for decisions about specific documents.