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Authentication KPI Library

Canonical definitions of passkey & authentication 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 ErrorsTotal Auth Attempts\text{AER}=\frac{\text{Auth Attempts with Explicit Errors}}{\text{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 StartMethod Attempts started\text{LSR}=\frac{\text{Logins succeeded after Method Start}}{\text{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 succeededPasskey Auth Attempts started\text{PASR}=\frac{\text{Passkey Auth Attempts succeeded}}{\text{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 completedAuth Attempts started\text{ADoR}=\frac{\text{Auth Attempts started}-\text{Auth Attempts completed}}{\text{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\text{TTA}=\text{Auth completed Timestamp}-\text{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 startedLogin Attempts with Method offered\text{LCR}=\frac{\text{Login Attempts with Method started}}{\text{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 startedLogin Offers\text{LER}=\frac{\text{Login Attempts started}}{\text{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 UsersUsers offered Passkey Opportunity\text{PER}=\frac{\text{Enrolled Users}}{\text{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 LoginsTotal Logins\text{PUR}=\frac{\text{Passkey Logins}}{\text{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 ResetsActive Users⋅Time Period in Years\text{PRV}=\frac{\text{Total Password Resets}}{\text{Active Users}\cdot\text{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 AccountsActive Accounts\text{ATOR}=\frac{\text{Compromised Accounts}}{\text{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 TicketsTotal Support Tickets\text{AST}=\frac{\text{Auth Related Tickets}}{\text{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 succeededAuth Attempts started\text{TASR}=\frac{\text{Auth Attempts succeeded}}{\text{Auth Attempts started}}