July 22, 2026

What Criteria Do Analytics Engines Use to Flag Caller IDs?

Telecom giants use data analysis to flag caller IDs, and carriers like AT&T/Hiya, Verizon/TNS, and T-Mobile/First Orion use protocol checks and behavioral information to decide what to label as suspected spam.

The numbers most vulnerable to spam labels are those that reflect high-volume patterns typically associated with call centers. But that isn’t all the algorithm looks at. Here’s a breakdown of what can get you labeled as spam, and how you can protect your call center from getting the shaft.

1. Technical Authentication (STIR/SHAKEN)

Let’s start with the technical layer. This comes from your own telecom carrier, which tells call recipients whether they can trust you. The carrier uses the STIR/SHAKEN framework to evaluate the relationship between the number and the caller.

Carriers take this step to increase confidence in the phone system and to reduce user frustration. By helping to identify which calls might be spam, they help people screen out nuisance calls. But legitimate businesses might get caught up in the network carrier’s attempts to label fraudulent numbers.

There are three types of possible assignments from your carrier:

A-Level (Full Attestation): The carrier knows you and confirms your right to use the specific phone number.
B-Level (Partial Attestation): The carrier knows you but cannot verify that you can use that specific number.
C-Level (Gateway Attestation): The carrier knows where the call entered its network but has no information about the original caller. C-level calls are almost always flagged as “Suspected Spam.”‌

A-level attestation is pretty important for call centers. But it’s just the first step in a multi-stage process carriers use to flag caller IDs.

2. Behavioral Call Patterns (The “Analytics” Engine)

A-level attestation might be the first “stamp of approval” from a network carrier. But spam isn’t just about knowing who’s calling; it’s about caller behavior as well. So even legitimate businesses can be flagged for aggressive dialing patterns. If you use predictive dialers, you might face barriers here.

Here are some call behavior analytics that can lead carriers to flag caller IDs:

High Volume/Short Duration: When your voicemail drops callers in the absence of an agent, it can create a record that shows hundreds of calls in a short period, with each call lasting mere seconds.
Low Answer Rates: A specific phone number (DID) that has a very low response rate, say less than 5%, the analytics engine assumes this is an unwanted caller.
Neighbor Spoofing: This technique tricks recipients into answering by using a number that matches the first six digits of their own number. Engines now flag “bursts” of such calls from similar prefixes.
The “Inbound/Outbound” Ratio: Business numbers typically receive inbound calls. A number that makes only outbound calls and receives no inbound traffic is a major red flag.

Behavioral patterns are an important stage in the analytics engine’s decision to flag caller IDs, but there’s still another layer: what real people have to say.

3. Crowdsourced & Reputation Data

The final layer is made of “negative feedback” loops. These are ways the network carriers can identify potential scams or illegitimate call activity. They range from everyday people complaining to telecom carriers using old numbers to track potential new spam.

Here’s what carriers look at:

User Reports: Carriers identify an aggregate number of users who manually “report spam” on their smartphones for the same number.
Honeypots: Carriers keep once-active numbers they no longer assign to customers. If these numbers get incoming calls, the Caller ID is instantly blacklisted.
Third-Party Registries: Systems like Hiya, First Orion, and TNS maintain their own reputation scores (0–100). Once a score drops below a certain threshold (e.g., 60 or 70), they apply the “Spam Likely” tag.

Analytics Engines’ Criteria for Flagging Calls

Given these layers of analysis, you can create a simple cheat sheet to see what might get your calls labeled as spam. Each carrier is unique, but most will consider these factors:

Suspicious Calling Behavior

B or C Attestation Levels for STIR/SHAKEN
Sudden spikes in call volume (e.g., 0 to 500/hr)
Call durations consistently last under 15 seconds
Answer rates under 5%-10%
Unregistered or generic caller ID name (CNAM) registration

Legitimate Calling Behavior

A Attestation Levels for STIR/SHAKEN
Consistent and moderate calling behavior
Call durations vary, often more than 30 seconds.
Answer rates exceed 20%-30%
Verified business name or branded caller ID

How to Mitigate Flagging in Outbound Call Centers

Even legitimate outbound calling businesses get the “spam” label, so call centers have to adopt a comprehensive strategy to handle potential call flags. If you rely on outbound dialing, here are some ways to start protecting your call assets:

Register with the Free Caller Registry: This lets consumers look up your numbers to confirm they are not spam. The registry also sends your business data to the three major analytics providers simultaneously.
Monitor “Attestation”: Ensure your carrier is giving your calls Level A in the STIR/SHAKEN framework.
Remediate, Don’t Rotate: Discontinue the old strategy of using multiple direct inward dialing (DIDs) to avoid them “getting hot.” This is a band-aid fix. Instead, remediate your DIDs with carriers rather than swap out numbers.
Avoid “Cold” Dialing: Your lead lists speak volumes about the quality of your dialing. Cold calling random or uninterested parties can lead to higher rates of consumers reporting your numbers as spam.
Use Blended Phone Numbers: Use numbers with a history of inbound and outbound calls to appear more like a human user.
Monitor Outbound Numbers: Practice ongoing phone number monitoring to spot outbound caller IDs that receive negative call labels.

Partner With CIDR for a Call Strategy

CIDR supports your business strategy to tackle engines that flag caller IDs. Our services let you monitor flags, dialing activity, and call ID information. With this timely, accurate information, you can address compliance issues immediately.

Contact Caller ID Reputation today to stay ahead of call flags and consistently reach more of your customers.