Authentication KPI Library - Passkey & Auth Metrics

Reliability

Metrics measuring authentication system stability and success rates

Authentication Error Rate
Authentication Error Rate is the share of authentication attempts that end in an explicit error, helping to pinpoint reliability and UX failures.
AER=Auth Attempts with Explicit Errors / Total Auth Attempts

Login Success Rate
Share of login method attempts that result in a successful authenticated session, measured from the moment a user starts a method.
LSR=Logins succeeded after Method Start / Method Attempts started

Passkey Authentication Success Rate
Measures the share of passkey login attempts that reach an authenticated session, including user cancellations and technical failures.
PASR=Passkey Auth Attempts succeeded / Passkey Auth Attempts started

Friction & Speed

Metrics tracking user experience and authentication performance

Authentication Drop-Off Rate
The percent of authentication attempts that start but do not complete, showing where users abandon the login experience.
ADoR=(Auth Attempts started − Auth Attempts completed) / Auth Attempts started

Time to Authenticate
Time to Authenticate measures how long a login takes from starting the auth flow to reaching the authenticated state.
TTA=Auth completed Timestamp − Auth started Timestamp

Adoption

Metrics measuring passkey and passwordless adoption progress

Login Conversion Rate
Share of login attempts where a user starts a login method after being offered at least one option. Measures method choice and early funnel drop off.
LCR=Login Attempts with Method started / Login Attempts with Method offered

Login Engagement Rate
Login Engagement Rate measures how often users start a login attempt after being shown a login entry point, indicating intent and funnel health.
LER=Login Attempts started / Login Offers

Passkey Enrollment Rate
The share of users who create a passkey after being offered enrollment. It is the leading indicator for passkey adoption and future sign-in gains.
PER=Enrolled Users / Users offered Passkey Opportunity

Passkey Usage Rate
Measures the share of successful passkey logins from all successful logins, showing true preference and whether passkeys are the default path.
PUR=Passkey Logins / Total Logins

Fallback & Recovery

Metrics for fallback methods and account recovery flows

Password Reset Volume
Password Reset Volume tracks how many completed password resets occur per active user per year, helping quantify support load, friction and cost.
PRV=Total Password Resets / (Active Users ⋅ Time Period in Years)

Business Impact

Metrics connecting authentication to business outcomes

Account Takeover Rate
How often active accounts are confirmed compromised in a period, reported per 10,000 active accounts to quantify real security harm.
ATOR=Compromised Accounts / Active Accounts

Authentication Support Ticket Rate
Portion of all support tickets caused by login and authentication issues, used to quantify auth friction, support cost and improvement impact.
AST=Auth Related Tickets / Total Support Tickets

Total Authentication Success Rate
Total Authentication Success Rate measures how often login attempts end in a completed, authenticated session, including failures and abandonments.
TASR=Auth Attempts succeeded / Auth Attempts started