Evidence standards
Every statistic in Delta — and now on this site — carries one of four markers, defined in the book’s Appendix J. The site holds itself to the book’s standard.
| Marker | Meaning | Reader action |
|---|---|---|
| VERIFIED | The author accessed the public primary source. | Cite with confidence. |
| REPORTED | Named industry source; not independently audited. Vendor-sponsored figures tend to be more favorable and are weighed accordingly. | Cite with attribution; treat as directional. |
| OBSERVATIONAL | Professional pattern recognition from two decades of practice; illustrative magnitudes, not measurements. | Treat as experienced judgment, not data. |
| ILLUSTRATIVE SCENARIO | Author-constructed teaching example demonstrating a documented failure mechanism. | Use as a teaching aid. Do not cite as a case study. |
Why constructed scenarios exist — and why they’re marked
The failure mechanisms are real and documented in published post-mortems; the named people, companies, and dollar figures are constructed so that no client or employer material is ever used. Marking them is what keeps the teaching honest.
Corrections
Errors are corrected in public at /errata/. To report one: errata@acuity.press. Showing corrections beats pretending to need none.