Measure more than adoption counts. Track how often users fall back to weaker methods, how many support tickets involve recovery, whether managed-device coverage is high enough, and whether phishing-related incidents decline after rollout. If fallback remains common, the programme is not yet delivering its intended assurance.
Why This Matters for Security Teams
Passkey adoption can look healthy on a dashboard while the control is still failing in practice. IAM teams need to know whether passkeys are reducing credential risk, or simply adding another sign-in option that users bypass under pressure. The right measure is assurance: fewer phishing-prone logins, less dependence on SMS or password resets, and less operational friction after rollout. NIST Cybersecurity Framework 2.0 treats identity as an ongoing risk function, not a one-time launch metric.
That distinction matters because fallback paths often become the real attack surface. If users can still recover with weak methods, adversaries do not need to defeat the passkey itself. In parallel, unsupported device states and inconsistent recovery flows can push users back to passwords, which defeats the point of the programme. NHI Management Group has made a similar point in other identity contexts: weak controls hide behind “working” adoption numbers until incident data exposes the gap, as seen in its Ultimate Guide to NHIs and Azure Key Vault privilege escalation exposure.
In practice, many security teams discover passkey weakness only after phishing reports stay flat or recovery tickets surge, rather than through a deliberate assurance review.
How It Works in Practice
Effective measurement starts with separating enrollment from assurance. Enrollment tells you how many users have a passkey registered. Assurance tells you whether passkeys are actually being used as the primary, successful, and resistant method for authenticating users. Security teams should track sign-in method mix, fallback frequency, recovery volume, device coverage, and post-rollout incident trends together, because any single metric can mislead.
Useful indicators include:
- Primary use rate: the percentage of successful logins completed with passkeys rather than passwords, SMS, or push approval.
- Fallback rate: how often users abandon passkeys and complete authentication through weaker methods.
- Recovery dependency: tickets tied to lost devices, re-enrolment, or helpdesk-assisted account restoration.
- Managed-device coverage: the share of the workforce whose endpoint estate can reliably support the passkey policy.
- Security outcome shift: whether phishing-related incidents, MFA fatigue events, or account takeover attempts decline after rollout.
Implementation should also reflect policy design. If the organisation permits multiple authenticators, teams need to know which paths are preferred, which are allowed only for exception cases, and which are effectively legacy debt. That is why identity telemetry should be reviewed alongside device posture and access policy, not in isolation. Current guidance suggests passkey programmes work best when rollout is paired with stronger recovery controls, clear exception handling, and user segmentation for managed versus unmanaged devices. NIST CSF 2.0 is useful here because it encourages measuring identity controls against operational outcomes, not just deployment status.
A useful external benchmark is the NIST Cybersecurity Framework 2.0, which helps anchor measurement in risk reduction rather than vanity adoption. These controls tend to break down when mixed-device environments and legacy recovery channels force users onto alternate paths too often.
Common Variations and Edge Cases
Tighter passkey enforcement often increases support load at first, so organisations need to balance assurance gains against recovery overhead and user readiness. That tradeoff is especially visible in BYOD-heavy environments, contractor populations, and regions where device management is inconsistent.
There is no universal standard for this yet, but current guidance suggests different groups need different thresholds. For managed corporate devices, passkey success rates should be high and fallback should be rare. For unmanaged devices, a lower passkey success rate may be acceptable if the organisation has deliberately constrained the risk and monitored recovery paths. Hybrid estates also complicate measurement because platform support, browser behaviour, and sync policies can vary enough to distort adoption data.
Teams should be careful with recovery metrics too. A spike in recovery tickets can mean the programme is immature, but it can also mean users are moving from unsafe password resets into safer governance-backed recovery. The key is whether recovery is controlled, logged, and rare enough to avoid becoming the new normal. That is why the most useful programme review combines usability, recovery, and security outcome data instead of treating passkey deployment as the end state. NHI Management Group’s research on lifecycle control and visibility is a useful reminder that identity controls fail when organisations confuse possession of a mechanism with actual operational control.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST CSF 2.0, NIST SP 800-63 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AA | Identity assurance should be measured by auth outcomes, not enrollment counts. |
| NIST SP 800-63 | IAL2 | Passkey assurance depends on the strength of identity proofing and authenticator binding. |
| NIST Zero Trust (SP 800-207) | PR.AC-1 | Zero trust requires continuous evaluation of access paths and authentication signals. |
Track authentication success, fallback, and recovery rates as evidence of identity control effectiveness.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on June 23, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
