Firefox desktop

Metrics and statistics that get computed for every firefox_desktop experiment.

opmon-config

Metrics

`qualified_cumulative_days_of_use`

QCDOU

The number of days in the interval that each client sent a main ping, given that the client had >0 active hours and >0 URIs loaded.

Analysis Periods: daily

Data Source: clients_daily

Statistics: mean

Definition:

COUNTIF(
    active_hours_sum > 0 AND
    scalar_parent_browser_engagement_total_uri_count_normal_and_private_mode_sum > 0
)

`ad_clicks`

Ad clicks

Counts clicks on ads on search engine result pages with a Mozilla partner tag.

Analysis Periods: daily

Data Source: search_clients_engines_sources_daily

Statistics: mean

Definition:

COALESCE(SUM(ad_click), 0)

`days_of_use`

Days of use

The number of days in the interval that each client sent a main ping.

Analysis Periods: daily

Data Source: clients_daily

Statistics: mean

Definition:

COUNT(submission_date)

`uri_count`

URIs visited

Counts the total number of URIs visited. Includes within-page navigation events (e.g. to anchors).

Analysis Periods: daily

Data Source: clients_daily

Statistics: mean

Definition:

COALESCE(SUM(scalar_parent_browser_engagement_total_uri_count_sum), 0)

`search_count`

SAP searches in Glean

Counts the number of searches a user performed through Firefox's Search Access Points. Learn more in the search data documentation.

Analysis Periods: daily

Data Source: search_clients_engines_sources_daily

Statistics: mean

Definition:

COALESCE(SUM(sap), 0)

`retained`

Retained

Records whether a client submitted any pings (i.e. used Firefox).

Analysis Periods: daily

Data Source: clients_daily

Statistics: mean

Definition:

IF(COALESCE(SUM(pings_aggregated_by_this_row), 0) > 0, 1, 0)

`active_hours`

Active hours

Measures the amount of time (in 5-second increments) during which Firefox received user input from a keyboard or mouse. The Firefox window does not need to be focused.

Analysis Periods: daily

Data Source: clients_daily

Statistics: mean

Definition:

COALESCE(SUM(active_hours_sum), 0)

jetstream-config

Source | Edit

Metrics

`daily_active_users_per_1000_clients_legacy`

DAU per 1,000 clients

This metric uses our canonical, supported definition of Daily Active Users (DAU), expressed in a format suited for use in experiments. In an experimental comparison, it describes the additional (incremental) DAU seen on each day from a treatment.

The units are expressed in terms of thousands of clients enrolled or exposed, so the effect can be scaled to either the observed or expected rollout population as needed to estimate absolute DAU impact.

Effects are averaged to a per-day basis over each analysis period. Since feature changes often show a strong "novelty effect", this metric is best interpreted over Week 4 or later, in order to better estimate what the lasting steady-state effects are.

Analysis Periods: weekly , overall , daily , preenrollment_weekly

Data Source: firefox_desktop_active_users_view

Statistics: linear_model_mean

Definition:

COUNTIF(is_dau) * 1000

`active_in_last_3_days_legacy`

3 Days Retention

Records whether a client submitted any pings (i.e. used Firefox) on any of the last 3 days. Uses legacy telemetry.

Analysis Periods: daily

Data Source: firefox_desktop_active_users_view

Statistics: binomial

Definition:

COALESCE(MIN(mozfun.bits28.days_since_seen(days_active_bits)), 30) < 3

`search_count`

SAP searches in Glean

Counts the number of searches a user performed through Firefox's Search Access Points. Learn more in the search data documentation.

Analysis Periods: overall , preenrollment_days28 , daily , weekly , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(sap), 0)

`active_hours`

Active hours

Measures the amount of time (in 5-second increments) during which Firefox received user input from a keyboard or mouse. The Firefox window does not need to be focused.

Analysis Periods: overall , preenrollment_days28 , daily , weekly , preenrollment_weekly

Data Source: clients_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(active_hours_sum), 0)

`client_level_daily_active_users_v2`

Firefox Desktop Client-Level DAU

Client-level DAU. The logic is detailed on the Confluence DAU page and is automatically cross-checked, actively monitored, and change controlled. This metric needs to be aggregated by submission_date. If it is not aggregated by submission_date, it is similar to a "days of use" metric, and not DAU.

Analysis Periods: overall , preenrollment_days28 , daily , weekly , preenrollment_weekly

Data Source: firefox_desktop_active_users_view

Statistics: per_client_dau_impact

Definition:

COUNTIF(is_dau)

`unenroll`

Unenrollments

Counts the number of clients with an experiment unenrollment event.

Analysis Periods: daily

Data Source: normandy_events

Statistics: binomial

Definition:

COALESCE(LOGICAL_OR(        event_category = 'normandy'
        AND event_method = 'unenroll'
        AND event_string_value = '{experiment_slug}'
     ), FALSE)

`retained_dau`

Retained (DAU)

Whether the client had at least one DAU-qualifying day in the analysis window (is_dau = TRUE on any day).

Conventionally expressed as a percentage rate: The percentage of clients from the originating cohort that were then active in the later period.

Most typically, this is measured as Week 2 Retention in order to balance timeliness and accuracy. But when time permits, Data Science recommends using Week 4 Retention as more representative of long-term effects.

Analysis Periods: weekly , daily

Data Source: firefox_desktop_active_users_view

Statistics: binomial

Definition:

COALESCE(LOGICAL_OR(is_dau), FALSE)

`retained`

Retained

Records whether a client submitted any pings (i.e. used Firefox).

Note: As of June 2026, this metric is being deprecated in favor of "Retained (DAU)", which better matches the conventional definition of Retention based on "active" instead of "seen" now recommended by Data Science team and used for reporting in other contexts.

Analysis Periods: weekly , daily

Data Source: clients_daily

Statistics: binomial

Definition:

COALESCE(SUM(pings_aggregated_by_this_row), 0) > 0

`is_default_browser`

Is Default Browser

Was Firefox the default browser at any point during the interval?

Analysis Periods: overall , preenrollment_days28 , weekly , preenrollment_weekly

Data Source: clients_daily

Statistics: binomial

Definition:

COALESCE(LOGICAL_OR(is_default_browser), FALSE)

`qualified_cumulative_days_of_use`

QCDOU

The number of days in the interval that each client sent a main ping, given that the client had >0 active hours and >0 URIs loaded.

Analysis Periods: overall , preenrollment_days28 , weekly , preenrollment_weekly

Data Source: clients_daily

Statistics: linear_model_mean, deciles

Definition:

COUNTIF(
    active_hours_sum > 0 AND
    scalar_parent_browser_engagement_total_uri_count_normal_and_private_mode_sum > 0
)

`uri_count`

URIs visited

Counts the total number of URIs visited. Includes within-page navigation events (e.g. to anchors).

Analysis Periods: overall , preenrollment_days28 , weekly , preenrollment_weekly

Data Source: clients_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(scalar_parent_browser_engagement_total_uri_count_sum), 0)

`days_of_use`

Days of use

The number of days in the interval that each client sent a main ping.

Analysis Periods: overall , preenrollment_days28 , weekly , preenrollment_weekly

Data Source: clients_daily

Statistics: linear_model_mean, empirical_cdf, deciles

Definition:

COUNT(submission_date)

`ad_clicks`

Ad clicks

Counts clicks on ads on search engine result pages with a Mozilla partner tag.

Analysis Periods: overall , preenrollment_days28 , weekly , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(ad_click), 0)

`tagged_follow_on_search_count`

Tagged follow-on searches

Counts the number of follow-on searches with a Mozilla partner tag. These are additional searches that users performed from a search engine results page after executing a tagged search through a SAP. Learn more in the search data documentation.

Analysis Periods: overall , preenrollment_days28 , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(tagged_follow_on), 0)

`tagged_search_count`

Tagged SAP searches

Counts the number of searches a user performed through Firefox's Search Access Points that were submitted with a partner code and were potentially revenue-generating. Learn more in the search data documentation.

Analysis Periods: overall , preenrollment_days28 , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(tagged_sap), 0)

`searches_with_ads`

Search result pages with ads

Counts search result pages served with advertising. Users may not actually see these ads thanks to e.g. ad-blockers. Learn more in the search analysis documentation.

Analysis Periods: overall , preenrollment_days28 , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(search_with_ads), 0)

`organic_search_count`

Organic searches

Counts organic searches, which are searches that are not performed through a Firefox SAP and which are not monetizable. Learn more in the search data documentation.

Analysis Periods: overall , preenrollment_days28 , preenrollment_weekly

Data Source: search_clients_engines_sources_daily

Statistics: linear_model_mean, deciles

Definition:

COALESCE(SUM(organic), 0)