Research · 2 min read
You Have Cameras. Do They Cover the Places That Actually Matter?
Camera count is a poor proxy for usable coverage; priority points and failure causes lead to better fixes.
Twenty cameras, a clean grid of feeds, a monitoring contract signed — none of it answers the only question that matters: can you see the places trouble would actually come from? Our assessments name five such places before looking at a single camera. Across 30 consecutive properties, 25 had at least one of the five blind.
Our analysis of 150 priority-point observations across 30 properties, 30 consecutive property assessments.
Should a property add cameras before auditing the views it already has?
Across 150 priority points in 30 consecutive property assessments, 25 properties had at least one blind priority point and 62.5% of blind points were attributed to field-of-view or fixed-obstruction problems. Audit the views before adding hardware.
The numbers behind the answer
Selected measures only. Denominators and interpretation stay attached so the headline cannot stand alone.
83.3%
Properties with a blind priority point
25 of 30 assessed properties had at least one of five priority points rated blind.
26.7%
Blind priority points
40 of 150 assessed priority points were outside usable coverage.
62.5%
Field-of-view or fixed-obstruction causes
25 of 40 blind points were attributed to those two causes.
A property can have cameras and still miss a priority view
The audit starts before any camera talk: name five priority points — the entrances, the loading area, the approach paths, the spots an incident would have to cross — then check whether each has a usable view. Across 30 properties, 25 had at least one blind point. The median property was blind on one of its five.
That's why camera count is a weak way to buy security. Ten cameras aimed at the wrong places cover less than six aimed at the right ones. Coverage is a property of aiming, obstruction, light, and uptime — not of the invoice.
First action
Audit the views you need before deciding how much hardware to add.
Most blind points call for diagnosis—not an automatic camera purchase
The 40 blind points failed for six different reasons, and the mix is the useful part. Outside the field of view: 16. Fixed obstruction: 9. Insufficient light: 7. Glare: 5. Resolution too low at distance: 2. Camera simply offline: 1.
Each cause has its own fix, and most aren't "buy another camera." Field of view is an aiming or mounting job. Obstruction is a layout or overlap change. Light and glare need day-and-night tests. Resolution needs an identification test at real distance. Offline is maintenance and health monitoring. Diagnosis first, hardware second.
Evidence visual
Observed cause among 40 blind priority points
Shares use blind points—not all assessed points—as the denominator. Cause labels describe the primary recorded reason.
Run the audit in the conditions the view has to handle
The audit is repeatable, and the conditions it runs in matter as much as the checklist. A view that works at noon can be useless at 2 a.m. Define the point and the visual task — detection, recognition, identification — then test framing, obstructions, light, glare, resolution at distance, and system health, in daylight and darkness where both matter.
What this aggregate can't tell you: whether fixing a blind point prevents losses (no incident data was joined to the gaps), or whether night blindness exceeds day blindness in general (that needs its own denominators). What it can tell you is where to look first. Re-run it after any layout, lighting, or landscaping change.
- Name each priority point and required visual task.
- Check frame coverage and likely path of travel.
- Check fixed and changing obstructions.
- Test daylight, low light, glare, and weather-relevant conditions.
- Verify resolution at actual distance and monitor uptime.
- Reassess after layout, lighting, landscaping, or operational changes.
Questions property teams ask
What counts as a functional blind spot?
A priority point is blind when it has no view or the available view cannot perform the predefined visual task. The exact rubric should be documented for each assessment.
Is a blind spot always fixed by adding another camera?
No. Aiming, mounting, obstruction, lighting, glare, resolution, or uptime can be the primary issue; each requires a different remedy.
How often should camera views be reassessed?
Reassess after layout, lighting, landscaping, access, or equipment changes and on a regular maintenance cadence appropriate to the property.
Does one blind point mean the whole camera system is ineffective?
No. It identifies one unmet priority view. The operational importance depends on the point and the task the system must support there.
Our methods, limits, and sources
How we calculated this
This is original 911 Sentinel research — we gathered the records, ran every calculation below, and published the aggregate dataset.
We recorded five predefined priority points per property across 30 consecutive assessments, rated whether each has usable coverage, and assigned a primary cause to blind points.
- We validated property, priority-point, context, visibility, cause, and review fields.
- We calculated point-level and equal-property-weighted blind shares.
- We counted properties with at least one blind point and the distribution of blind counts.
- We ranked causes and preserved denominators for property, point-type, and context cross-tabs.
What this analysis cannot establish
- The aggregate covers 30 properties and five predefined priority points per property.
- Site selection, property mix, dates, and the exact usable-view rubric affect generalization.
- The current result does not report independent inter-rater agreement or linked before/after reassessments.
- No incident-outcome join supports a prevention or loss-reduction claim.
- Context counts are not context-specific blind rates without denominators.
Sources
This study is 911 Sentinel's own work, built from our operational records.
Related questions and practical guides
New coverage — intake open
Audit the priority views before expanding the system
A site assessment can define the important views, test the existing system in relevant conditions, and separate adjustment, maintenance, lighting, and hardware needs.