[{"name":"SDS 2.4.11 Synthetic A/A Test","machine_readable_name":"sds2-4-11-synth-aa-test","description":"An A/A test to test the Experimentation Platform end to end (XLab -> Varnish -> MediaWiki -> Data Lake).","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control-2","machine_readable_name":"control-2","description":"No changes for subjects in this group.","split":0.5}],"start_date":"2025-06-06","end_date":"2025-06-12"},{"name":"SDS 2.4.11 Synthetic A/A Test 2","machine_readable_name":"sds2-4-11-synth-aa-test-2","description":"An A/A test to test the Experimentation Platform end to end (XLab -> Varnish -> MediaWiki -> Data Lake).","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","description":"No changes for subjects in this group.","split":0.5}],"start_date":"2025-06-20","end_date":"2025-06-27"},{"name":"Logged-in Synthetic A/A Test (JS SDK)","machine_readable_name":"synth-aa-test-mw-js","description":"This is to verify that we can run a synthetic A/A test on logged-in visitors using the JS SDK","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Contol 2","machine_readable_name":"control-2","description":"This is an A/A test, so no changes for subjects in this group.","split":0.5}],"start_date":"2025-08-07","end_date":"2025-08-14"},{"name":"FY25-26 WE3.6.1 Retention AA Test","machine_readable_name":"we-3-6-1-retention-aa-test1","description":"Smoke Test for Test Wiki ONLY\nHypothesis: If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2025-07-24","end_date":"2025-07-31"},{"name":"FY25-25 WE3.6.1 Retention E2E AA Test","machine_readable_name":"we-3-6-1-retention-aa-test2","description":"Actual Test for ALL Wikis Hypothesis: If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2025-07-30","end_date":"2025-08-31"},{"name":"Donation Link (Phase II)","machine_readable_name":"we-3-2-3-donate-ab-test-1","description":"A/B test on anonymous users  to track clicks on the different versions of  donation link to study whether the following hypothesis is correct: \"Increasing the prominence of entry points to donations in the logged-out experience of the Minerva mobile web  and Vector desktop will increase the click-through rate of the donate link by 30%.\"","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"More prominent donation entry point.","split":0.5}],"start_date":"2025-08-12","end_date":"2025-09-12"},{"name":"fy24-25-we-1-7-rc-grouping-toggle","machine_readable_name":"fy24-25-we-1-7-rc-grouping-toggle","description":"Group by toggle experiment for RecentChanges/Watchlist/RelatedChanges","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"toggle-shown","machine_readable_name":"toggle-shown","description":"Group by toggle is present.","split":0.5}],"start_date":"2025-08-11","end_date":"2025-09-22"},{"name":"Logged-in Synthetic A/A Test (PHP SDK)","machine_readable_name":"synth-aa-test-mw-php","description":"The purpose of this synthetic A/A test is to verify that the Experimentation Platform is capable of running a test on all visitors using the PHP SDK.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","description":"No changes for subjects in this group","split":0.5}],"start_date":"2025-10-29","end_date":"2025-11-06"},{"name":"FY25-26 WE 3.1.5 MinT for Readers AA test","machine_readable_name":"fy25-26-we-3-1-5-mint-readers","description":"A/A test to establish baseline mobile reader retention for MinT for Readers","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control_2","split":0.5}],"start_date":"2025-09-22","end_date":"2025-10-13"},{"name":"WE 4.2.7 hCaptcha on French Wikipedia A/B","machine_readable_name":"hcaptcha-on-french-wikipedia","description":"As part of the hCaptcha trial, we plan to release the hCaptcha feature to 90% of users accessing the Special:CreateAccount on French wikipedia, while displaying FancyCaptha to 10% of users. This will help ensure that there is no detectable effect on existing performance metrics[1], such as time spent understanding the form before first interaction, interactions with different UI components, etc.\n\nAs the UI does not allow to input more than 10%, we left the input as 10% but would like to clarify that the splitting of the experimentation on frwiki should be in such a way that 90% of users see hCaptcha loaded on Special:CreateAccount, while 10% see FancyCaptha, as per the Slack discussion[2].\n\n[1] https://docs.google.com/spreadsheets/d/1f7VGnkYVZZ5tJJKeVDq9xhCClVhX0kXb_mEmM_iesQg/edit?gid=0#gid=0\n[2]https://wikimedia.slack.com/archives/C01DFMX6QLB/p1757502866154529.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Users viewing FancyCaptcha","machine_readable_name":"user-viewing-fancy-captcha","description":"We would like to clarify that the splitting of the experimentation on frwiki should be in such a way that 90% of users see hCaptcha loaded on Special:CreateAccount, while 10% see FancyCaptha, as per the Slack discussion[1][1]https://wikimedia.slack.com/archives/C01DFMX6QLB/p1757502866154529.","split":0.5}],"start_date":"2025-10-06","end_date":"2025-12-09"},{"name":"xLab MediaWiki Module Loaded","machine_readable_name":"xlab-mw-module-loaded","description":"Sends events when the xLab Javascript SDK is loaded and sends an image beacon in the BeforePageDisplay hook given the right configuration variables.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2025-10-28","end_date":"2025-11-04"},{"name":"Reading List A/B Test","machine_readable_name":"we-3-3-4-reading-list-test1","description":"Hypothesis:\nIf we give logged-in readers the ability to save articles to a private reading list, we expect engagement on the site to increase, as measured by a 5% increase in internal referral traffic for readers who use the feature, and a statistically significant increase for all users.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2025-11-12","end_date":"2026-07-01"},{"name":"xLab MediaWiki Module Loaded v2","machine_readable_name":"xlab-mw-module-loaded-v2","description":"Sends an event when the xLab Javascript SDK is loaded and sends an image beacon in the BeforePageDisplay hook given the right configuration variables.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2025-11-06","end_date":"2025-11-12"},{"name":"Reading List A/B Test (English)","machine_readable_name":"we-3-3-4-reading-list-test1-en","description":"Hypothesis: If we give logged-in readers the ability to save articles to a private reading list, we expect engagement on the site to increase, as measured by a 5% increase in internal referral traffic for readers who use the feature, and a statistically significant increase for all users. (note, this is the English version of this experiment for the staggered rollout)","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2025-11-19","end_date":"2026-07-01"},{"name":"Logged-out retention AA test round 2","machine_readable_name":"logged-out-retention-round2","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2025-11-21","end_date":"2025-12-21"},{"name":"FY25-26 WE4.2 hCaptcha editing","machine_readable_name":"fy25-26-we-4-2-hcaptcha-editing","description":"A/B test of FancyCaptcha and hCaptcha where users enrolled in the experiment at all (in either of the two \"control\" groups) will be prompted with FancyCaptcha when they try to save an edit, while the remaining 90% of the users (those not enrolled in the experiment) will be prompted with hCaptcha when they try to save an edit.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Also control","machine_readable_name":"control-2","description":"This is a second control group. The end result is for 90% of traffic to get hCaptcha, and 10% to get FancyCaptcha","split":0.5}],"start_date":"2025-11-19","end_date":"2026-01-19"},{"name":"Synthetic A/A Test Traffic Impact","machine_readable_name":"synth-aa-test-traffic-impact","description":"Experiment-specific instrument that sends a \"page-visited\" event if the user is enrolled in the experiment below","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-01-12","end_date":"2026-02-09"},{"name":"FY25-26 WE 1.1.19 Mobile Web Section Editing Dead End A/B Test","machine_readable_name":"fy25-26-we-1-1-19-mobile-section-dead-end-phase-2","description":"Offer people in section editing on mobile web a button to edit the full page. NOTE: Per T415129, experiment was re-analyzed after the fact. While experiment was conducted on 100 wikis, the re-analysis was manually restricted to just 67 (Wikipedias only) per original plans.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2025-12-15","end_date":"2026-01-12"},{"name":"Test Kitchen MediaWiki Module Loaded","machine_readable_name":"test-kitchen-mw-module-loaded","description":"Sends an event when the Test Kitchen Javascript SDK is loaded.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-01-15","end_date":"2026-01-17"},{"name":"Test Kitchen Synthetic A/A Test PHP SDK","machine_readable_name":"synth-aa-test-mw-php-tk","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-01-15","end_date":"2026-01-17"},{"name":"Revise tone newcomer task","machine_readable_name":"growthexperiments-revise-tone","description":"Hypo WE1.1.18: If we analyze a predetermined set of leading indicators ~2 weeks after the start of the Revise Tone Structured Task A/B test, we will be able to identify what – if any – facets of the end-to-end experience need to be adjusted or investigated before we can be confident evaluating the impact of the feature.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"The Revise Tone task is available on the Newcomer Homepage, enabled by default. It will also be available in the post-edit panel after completing a structured task.","split":0.5}],"start_date":"2026-03-31","end_date":"2026-07-24"},{"name":"Synth Test New External Path","machine_readable_name":"synth-test-new-external-path","description":"A synthetic experiment to test the new external path that Test Kitchen will be sending events originating from instruments and logged-in experiments to. Currently running part 2 of the test.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-03-12","end_date":"2026-03-26"},{"name":"WMDE/TechWish Green Button Test","machine_readable_name":"test-context-edit-color","description":"WMDE Technical Wishes wants to try out AB testing to see what needs to be done when we actually use the tool.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Green button","machine_readable_name":"green-button","description":"Context item edit button gets a subtle green background color","split":0.5}],"start_date":"2026-01-31","end_date":"2026-02-06"},{"name":"Synthetic A/A/A Test (JS SDK)","machine_readable_name":"synth-aaa-test-mw-js","description":"Validates the ability to run A/A/A tests.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.3333333333333333},{"name":"A","machine_readable_name":"treatment-group-a","split":0.3333333333333333},{"name":"B","machine_readable_name":"treatment-group-b","split":0.3333333333333333}],"start_date":"2026-02-05","end_date":"2026-02-09"},{"name":"Minerva Experiment AAA","machine_readable_name":"minerva-experiment-aaa","description":"Run a synthetic AAA test recreating the structure of Reader Growth's mobile-toc-abc test to determine uniform bucket distribution.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.3333333333333333},{"name":"Treatment 1","machine_readable_name":"treatment-1","split":0.3333333333333333},{"name":"Treatment 2","machine_readable_name":"treatment-2","split":0.3333333333333333}],"start_date":"2026-03-04","end_date":"2026-03-09"},{"name":"WE 1.8 FY25-26 Mobile Account Menu","machine_readable_name":"we-1-8-mobile-account-menu","description":"Hypothesis: If we add a user account button to the header on mobile web, then the number of new accounts created on mobile will increase by at least 2% relative to the control group.\nPlease note that users in the control group won't see the create account button in the hamburger menu or the log in and create account button in the account menu.  Users in the control and experiment group both see the log in button in the hamburger menu on mobile, because that button already existed before this experiment. Consequently, it is expected that there won't be any control group exposure to \"Hamburger menu create account link clickthrough,\" but there is control group exposure to \"Hamburger menu log in link clickthrough.\"","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"treatment","machine_readable_name":"treatment","description":"Users in this group will see the account menu in the top right heading when on mobile.","split":0.5}],"start_date":"2026-03-31","end_date":"2026-06-28"},{"name":"Logged-out Retention AA Test Round 3","machine_readable_name":"logged-out-retention-round3","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a  baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control-2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-09","end_date":"2026-03-30"},{"name":"Synthetic A/A Test Traffic Impact v2 1","machine_readable_name":"synth-aa-test-traffic-impact-1","description":"Experiment-specific instrument that sends a \"page-visited\" event if the user is enrolled in the experiment below","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-16","end_date":"2026-04-13"},{"name":"Synthetic A/A Test Traffic Impact v2 2","machine_readable_name":"synth-aa-test-traffic-impact-2","description":"Experiment-specific instrument that sends a \"page-visited\" event if the user is enrolled in the experiment below","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-16","end_date":"2026-04-13"},{"name":"Synthetic A/A Test Traffic Impact v2 3","machine_readable_name":"synth-aa-test-traffic-impact-3","description":"Experiment-specific instrument that sends a \"page-visited\" event if the user is enrolled in the experiment below.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-16","end_date":"2026-04-13"},{"name":"Logged-Out Warning Message","machine_readable_name":"growthexperiments-editattempt-anonwarning","description":"If we improve the logged out edit warning, the account creation rate among newcomers on mobile exposed to the warning will increase by at least 2% relative to the control group.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Gets a re-designed screen with the same 3 CTAs and an informative \"Learn more\" link","split":0.5}],"start_date":"2026-03-17","end_date":"2026-06-29"},{"name":"Attribution Research March 2026 Baseline","machine_readable_name":"attribution-research-short-baseline-run","description":"This is a limited version of a planned longer experiment.  It will help us establish baselines and is described in more detail here: https://docs.google.com/document/d/1vZgU41jeTdTDJqVXPy1T9dTpH8wRxuFWTfPgWBszdSY/edit?tab=t.pa2yncp7mfix.  Instrumentation plan linked from there.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"treatment","machine_readable_name":"treatment","description":"This is an A/A experiment where treatment is the same as control","split":0.5}],"start_date":"2026-03-17","end_date":"2026-04-02"},{"name":"Temporary Accounts Enrollment Test","machine_readable_name":"temp-accounts-enrollment-test","description":"A fake experiment just to understand how the system handles Temporary Accounts for logged-in experiments using mw-user identifier for enrollment. No data will be collected.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-20","end_date":"2026-03-25"},{"name":"Logged-out Retention AA Test Round 4","machine_readable_name":"logged-out-retention-round4","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-23","end_date":"2026-04-15"},{"name":"Logged-out Retention AA Test Round 5","machine_readable_name":"logged-out-retention-round5","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control-2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-03-31","end_date":"2026-04-23"},{"name":"Logged-out Retention AA Test Round 6","machine_readable_name":"logged-out-retention-round6","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control-2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-04-03","end_date":"2026-04-27"},{"name":"Sample experiment test","machine_readable_name":"sample-experiment-test","description":"Just a sample experiment for testing purposes","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-03-30","end_date":"2026-04-01"},{"name":"Logged-in Retention AA Test Round 1","machine_readable_name":"logged-in-retention-round1","description":"If we run an A/A test on retention rate for logged-in readers, we will establish a baseline for retention rate we can use for future quarters.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","description":"Second control group since it's an A/A test","split":0.5}],"start_date":"2026-04-01","end_date":"2026-05-01"},{"name":"Logged-out Retention AA Test Round 7","machine_readable_name":"logged-out-retention-round7","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-04-13","end_date":"2026-05-06"},{"name":"logged out retention round 8","machine_readable_name":"logged-out-retention-round8","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-04-24","end_date":"2026-05-18"},{"name":"WE1.8.3 Account Creation form improvements","machine_readable_name":"we-1-8-account-creation-form-v1","description":"Initial redesign of the account creation form toward a simpler, cleaner experience by following Codex design system guidelines, removing redundant elements, and improving information hierarchy.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-04-13","end_date":"2026-06-27"},{"name":"Account Creation Reading List CTA","machine_readable_name":"account-creation-reading-list-cta","description":"Evaluate the impact on account creation if we show the reading list bookmark button to logged-out users in Minerva, with a call-to-action to create an account. Part of FY25/26 WE 1.8.5.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Logged-out users who will see the bookmark button instead of the watchstar on mobile web","split":0.5}],"start_date":"2026-05-18","end_date":"2026-06-18"},{"name":"Incident Reporting System enwiki Trial","machine_readable_name":"incident_reporting_system_interaction","description":"The Incident Reporting System (IRS) is being introduced to address a gap identified in the Community Insights Report: a significant portion of contributors - especially newcomers - do not know how to get help when facing harassment or other issues. The trial is designed to validate whether the system: 1. Produces structured, actionable reports 2. Routes reports to the appropriate venues 3. Operates without introducing significant additional burden on functionaries","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":1}],"start_date":"2026-04-29","end_date":"2026-07-04"},{"name":"logged out retention round 9","machine_readable_name":"logged-out-retention-round9","description":"If we run an A/A test on retention rate for logged-out users, we will be able to establish a baseline for retention rate that we can use for comparison in future quarters.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-04-29","end_date":"2026-05-22"},{"name":"WE 1.10 Article Guidance","machine_readable_name":"we-1-10-articleguidance-v1","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Users who start their new articles using the Article Guidance workflow","split":0.5}],"start_date":"2026-05-27","end_date":"2026-08-29"},{"name":"logged out retention round 10","machine_readable_name":"logged-out-retention-round10","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-06","end_date":"2026-05-29"},{"name":"logged out retention round 11","machine_readable_name":"logged-out-retention-round11","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-13","end_date":"2026-06-06"},{"name":"logged out retention 12","machine_readable_name":"logged-out-retention-round12","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-20","end_date":"2026-06-12"},{"name":"logged out retention round 14","machine_readable_name":"logged-out-retention-round14","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-06-03","end_date":"2026-06-26"},{"name":"A/B test for email confirmation banner","machine_readable_name":"ab-test-email-confirmation-banner","description":"A/B testing for displaying an email confirmation nudge to users with unconfirmed emails","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"arm_a","machine_readable_name":"arm_a","description":"Arm with the banner exposed","split":0.5}],"start_date":"2026-05-06","end_date":"2026-05-22"},{"name":"FY25-26 WE 1.7.8 Suggestion Mode A/B Test","machine_readable_name":"fy25-26-we-1-7-8-suggestion-mode-beta","description":"Hypothesis 1.7.8: If we present junior contributors who enter the mobile VisualEditor with immediately actionable edit suggestions, then the proportion of edit sessions that result in someone publishing a constructive edit will increase by >=10%.","sampling_unit":"mw-user","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-05-21","end_date":"2026-07-15"},{"name":"Synthetic A/A (Non-cache-splitting) 1","machine_readable_name":"synth-aa-ncs-1","description":"The first test to prove that non-cache-splitting experiments can be run via Test Kitchen.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-15","end_date":"2026-05-22"},{"name":"Donor Delight Badge","machine_readable_name":"donor-delight-badge","description":"If we offer logged-out donors on mobile web a persistent Thank You badge by default that triggers a brief delightful interaction upon tap (C), then we will see a 1% improvement in 21-day cumulative retention rate (Update 2026-06-11: 30 days experiment active) compared to having a badge with a simple popover message (B), and users who do not get a badge at all post-donation (A). We will also track whether a larger percentage of donors in group (C) tap on the badge again in at least one future return session compared to those in (B), to inform whether playful interactions create a re-engagement loop.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.3333333333333333},{"name":"Treatment B: Simple","machine_readable_name":"treatment-b-simple","description":"Simple popover message (B).","split":0.3333333333333333},{"name":"Treatment C: Delightful","machine_readable_name":"treatment-c-delightful","description":"Brief delightful interaction upon tap (C).","split":0.3333333333333333}],"start_date":"2026-06-18","end_date":"2026-07-18"},{"name":"WE1.8.3 Account Creation form improvements II","machine_readable_name":"we-1-8-account-creation-form-v2","description":"Second round of redesign of the account creation form. Improved username live validation, clearer username policy popover and added reveal password button.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-06-12","end_date":"2026-06-30"},{"name":"Hoisting Error Detection Test 1","machine_readable_name":"synth-aa-detect-hoisting-errors-1","description":"This experiment is used to detect \"hoisting errors\" – an error triggered by a mismatch between the `experiment.enrolled` and `.assigned` event fields and the internal experiment enrollment header sent by Varnish to EventGate, the event intake service – and associate them with a user agent string so that we can validate or invalidate the hypothesis that hoisting errors affect a specific user agent.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Control 2","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-27","end_date":"2026-06-03"},{"name":"logged out retention round13","machine_readable_name":"logged-out-retention-round13","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-05-27","end_date":"2026-06-19"},{"name":"Attribution Research June 2026","machine_readable_name":"attribution-research-2026-06-run","description":"This is a full run of the Attribution Research experiment, baselined in March 2026.  Described in more detail here: https://docs.google.com/document/d/1vZgU41jeTdTDJqVXPy1T9dTpH8wRxuFWTfPgWBszdSY/edit?tab=t.pa2yncp7mfix","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","split":0.5}],"start_date":"2026-06-02","end_date":"2026-07-07"},{"name":"logged out retention round 16","machine_readable_name":"logged-out-retention-round16","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-06-17","end_date":"2026-07-10"},{"name":"NCS CORS Test","machine_readable_name":"ncs-cors-test","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":1}],"start_date":"2026-06-10","end_date":"2026-06-15"},{"name":"logged out retention round 15","machine_readable_name":"logged-out-retention-round15","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-06-10","end_date":"2026-07-03"},{"name":"logged out retention round 17","machine_readable_name":"logged-out-retention-round17","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-06-24","end_date":"2026-07-17"},{"name":"logged out retention round 18","machine_readable_name":"logged-out-retention-round18","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-07-01","end_date":"2026-07-24"},{"name":"logged out retention round 19","machine_readable_name":"logged-out-retention-round19","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-07-08","end_date":"2026-07-31"},{"name":"logged out retention round 20","machine_readable_name":"logged-out-retention-round20","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"control","machine_readable_name":"control-2","split":0.5}],"start_date":"2026-07-15","end_date":"2026-08-07"},{"name":"WMDE/Reader Footnote Click Intent","machine_readable_name":"cite-footnote-content-interaction-experiment","description":"We're trying to understand reader and contributor engagement with the reference list. In this A/B test we try to look into the readers interaction with footnotes and references previews. We try to validate the assumption that most readers on desktop who click on a footnote marker do NOT intend to navigate to the reference list. They are satisfied with viewing all the bibliographic information and details in the pop-up/in-line.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Treatment group that gets the reference popup with an optional link to jump the the references list.","split":0.5}],"start_date":"2026-06-17","end_date":"2026-07-15"},{"name":"Temp Accounts WE1.8.6","machine_readable_name":"we-1-8-tempuser-post-edit","description":"If we limit competing calls to action and highlight the benefits of account creation, temporary account holders exposed to the experience will have a registration rate at least 5% higher than the control group.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Improved, simplified call to action","split":0.5}],"start_date":"2026-06-30","end_date":"2026-07-31"},{"name":"Account Creation: No Benefits on desktop","machine_readable_name":"we-1-8-account-creation-no-desktop-benefits","description":"The prior 1.8.3 experiments showed that simplifying the mobile account form, including not showing the benefits block, improved account creation rate. That benefits block introduces substantial complexity. If we can not show it anywhere, we can drop a substantial amount of non-trivial code.\n\nTo ensure that the benefits block does not have a substantial positive effect on desktop, we're running this experiment.\n\nThe only difference between control and treatment is that on desktop, treatment group does not have the benefits block.","sampling_unit":"edge-unique","groups":[{"name":"Control","machine_readable_name":"control","description":"The control group represents users who receive the existing experience. It serves as the benchmark for measuring the impact of the changes being tested.","split":0.5},{"name":"Treatment","machine_readable_name":"treatment","description":"Does not show the benefits block on desktop Special:CreateAccount","split":0.5}],"start_date":"2026-07-13","end_date":"2026-08-03"}]