An industry comparison can be numerically correct and still answer the wrong question. If a government category contains small local bodies while a banking category contains only the largest institutions, a difference in observed DNS policy may reflect selection rather than the industry. Standardise the entity definition, domain selection, collection window and classification rules before interpreting a gap.
Use a consistent unit
Choose whether the analysis counts entities, unique domains or message volume. These denominators are not interchangeable. For an entity-level study, define how several domains combine into one result and disclose partial coverage. For a domain-level study, explain how entities with large estates affect the distribution. A message-weighted result requires message evidence and cannot be inferred from a DNS crawl.
Show the composition before the rates
Report each sector’s entity count, unique-domain count, source date, unresolved mappings and query outcomes before computing a rate. Split overlapping categories under a predeclared rule. A difference can reflect frame coverage, classification or timing rather than sector behavior.
Audit a proposed comparison
Before publication, ask whether every sector uses the same source quality, collection rules, domain boundary and unresolved-result treatment. Show denominators and missingness beside any rate. Present central banks separately unless the study protocol explicitly assigns them elsewhere for a defensible reason. If the samples are not comparable, publish descriptive observations and explain what additional frame would support a fair comparison.
Apply a transparent hypothetical decision
Suppose a hypothetical comparison includes ten large banks selected from a current registry and ten government websites selected from memory. Even if both groups return eight candidate policy records, equal numerators do not make the frames comparable. Publish no sector ranking. First obtain defensible frames, reconcile entity/domain mappings and apply common collection and unresolved-result rules. Record this as a methodology hold, not a security failure for either sector. No domains were queried for this example.
Technical boundary and publication decision
RFC 9989 Sections 4.7, 4.10.1 and 5.3 distinguish record syntax, policy discovery and message evaluation. An exact-owner TXT observation is not full policy discovery. RFC 9990 Section 3.1 describes aggregate message evidence, which is separate from a domain crawl. RFC 2308 Section 2 distinguishes negative DNS responses; a client timeout is not proof of absence. Study-design choices here are editorial methodology, not statistical requirements prescribed by those RFCs. This teaching revision makes no historical pilot or national adoption finding; any later empirical result needs its own accessible, hash-bound data and independent method review.