STIR/SHAKEN Explained: Why Caller ID Authentication Matters

If your outbound calls are being labeled as "Spam Risk" or "Scam Likely," STIR/SHAKEN authentication is the solution.

What is STIR/SHAKEN?

STIR/SHAKEN is a framework of protocols and procedures designed to combat caller ID spoofing and restore trust in the telephone network.

STIR (Secure Telephony Identity Revisited) defines how calls are authenticated and verified.

SHAKEN (Signature-based Handling of Asserted information using toKENs) defines how this information is handled by carriers.

How STIR/SHAKEN Works

1. Originating carrier authenticates the call and assigns an attestation level (A, B, or C)

2. Digital signature is created and attached to the call as it traverses the network

3. Terminating carrier verifies the signature and checks attestation

4. Consumer phone may display a "Verified" checkmark or spam warning based on attestation

Attestation Levels

Full Attestation (A): The carrier verified the caller is authorized to use the calling number. This is what you want.

Partial Attestation (B): The carrier verified the call originated on its network but can't confirm the caller is authorized to use the number.

Gateway Attestation (C): The call came from a gateway and the carrier can't verify the caller or the number. Often flagged as spam.

Why This Matters for Contact Centers

Answer rates are plummeting. Studies show 50%+ of calls with "Spam Risk" labels go unanswered, directly impacting:

Sales conversion rates

Collection success rates

Customer satisfaction (legitimate calls go unanswered)

Campaign ROI

How to Achieve Full Attestation

1. Register your calling numbers with your voice service provider

2. Use direct network connections rather than reselling or aggregation

3. Avoid number spoofing — only use numbers you legally own or lease

4. Implement call verification with your carrier

5. Monitor your caller ID reputation using services like Free Caller Registry

Beyond STIR/SHAKEN: Caller ID Reputation

Even with full attestation, your numbers can be flagged as spam if:

Call volume spikes suddenly

Abandonment rates are too high (hang-ups before agent connects)

High complaint volumes

Calling known litigators or spam complaint filers

Best practices:

Warm up new numbers gradually

Keep abandonment rates below 3%

Honor opt-outs immediately

Use branded caller ID (CNAM) with your company name

Carrier-Specific Solutions

Major carriers offer enhanced caller ID services:

AT&T Call Protect

T-Mobile Scam Shield

Verizon Call Filter

Some vendors offer "branded calling" services that display your company name and logo on consumer phones, similar to how businesses appear in mobile apps.

Predictive Dialer Considerations

If you use a predictive dialer, ensure your vendor:

Supports STIR/SHAKEN signing

Offers caller ID reputation monitoring

Provides local presence with properly authenticated numbers

Includes abandonment rate management to stay below 3%

Explore our Predictive Dialers category for STIR/SHAKEN-compliant solutions.

Monitoring and Remediation

Check your numbers regularly:

Free Caller Registry — see how carriers label your numbers

Nomorobo Lookup — check complaint databases

Call your own numbers from different carriers to test labels

If flagged as spam:

1. Reduce call volume temporarily

2. File remediation requests with carriers and analytics providers

3. Check for compliance violations or high complaint rates

4. Consider rotating to new numbers if reputation is severely damaged

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Need help implementing STIR/SHAKEN? Contact us for vendor recommendations.