Issue with $experiment_started Events Not Appearing in Mixpanel

Marie d. · 2025-04-16 12:02:05.903242+00

I've set-up an event "$experiment_started" that is correctly triggered when one shows a variant of an A/B test. I can see the events in the "Events" tab. However, when I go to the Experiment section in Mixpanel, and I click on "Select an experiment", I can read "No valid $experiment_started events detected". What can be the reason?

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Issue with $experiment_started Events Not Appearing in Mixpanel | Mixpanel Community

2 comments

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kapa.ai
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Hi Marie d., Please stand by as I search the Mixpanel knowledge base for an AI-powered answer. I normally take about 15 seconds or so. In case AI cannot answer your question, feel free to reach out to Mixpanel support at mixpanel.com/get-support. If you have follow-up questions for this thread, please tag me again with your question: @kapa.ai <follow-up question> 👋
Feel free to ask a follow-up question once I've answered by mentioning me with @kapa.ai
kapa.ai
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It sounds like your $experiment_started events aren't being properly recognized by Mixpanel's Experiments report. For these events to be detected automatically in the Experiments section, they need to follow a specific format.Based on the knowledge sources, your $experiment_started events must include two specific properties: 1. "Experiment name" - the name of your experiment 2. "Variant name" - the name of the variant the user was assigned toHere's an example of how a properly formatted event should look: LBKSmixpanel.track('$experiment_started', {'Experiment name': 'Test', 'Variant name': 'v1'})LBKSThe most common reasons your events aren't being detected in the Experiments section include: - Missing or incorrectly named properties (they must be exactly "Experiment name" and "Variant name") - The experiment started outside the date range you've selected in the Experiments report (Mixpanel scans for experiments that began in the date range you've selected)According to the documentation, "Mixpanel will automatically populate the Experiment, Control, and Variant dropdowns within the report if sent in the proper format" and "Mixpanel scans for experiments that began in the date range you've selected for the report." Experiments: Measure the impact of your A/B testingI recommend checking: 1. That your event properties use the exact names "Experiment name" and "Variant name" 2. That you're looking at the correct date range in the Experiments report 3. That the events are being sent with the correct user identifiersIf you've verified all these and still have issues, you might want to contact Mixpanel Support for further assistance.
kapa.ai is still learning and improving, please let me know how I did by reacting below.
ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.

kapa.ai
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·
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Hi Marie d., Please stand by as I search the Mixpanel knowledge base for an AI-powered answer. I normally take about 15 seconds or so. In case AI cannot answer your question, feel free to reach out to Mixpanel support at mixpanel.com/get-support. If you have follow-up questions for this thread, please tag me again with your question: @kapa.ai <follow-up question> 👋
Feel free to ask a follow-up question once I've answered by mentioning me with @kapa.ai
kapa.ai
APP
·
·
It sounds like your $experiment_started events aren't being properly recognized by Mixpanel's Experiments report. For these events to be detected automatically in the Experiments section, they need to follow a specific format.Based on the knowledge sources, your $experiment_started events must include two specific properties: 1. "Experiment name" - the name of your experiment 2. "Variant name" - the name of the variant the user was assigned toHere's an example of how a properly formatted event should look: LBKSmixpanel.track('$experiment_started', {'Experiment name': 'Test', 'Variant name': 'v1'})LBKSThe most common reasons your events aren't being detected in the Experiments section include: - Missing or incorrectly named properties (they must be exactly "Experiment name" and "Variant name") - The experiment started outside the date range you've selected in the Experiments report (Mixpanel scans for experiments that began in the date range you've selected)According to the documentation, "Mixpanel will automatically populate the Experiment, Control, and Variant dropdowns within the report if sent in the proper format" and "Mixpanel scans for experiments that began in the date range you've selected for the report." Experiments: Measure the impact of your A/B testingI recommend checking: 1. That your event properties use the exact names "Experiment name" and "Variant name" 2. That you're looking at the correct date range in the Experiments report 3. That the events are being sent with the correct user identifiersIf you've verified all these and still have issues, you might want to contact Mixpanel Support for further assistance.
kapa.ai is still learning and improving, please let me know how I did by reacting below.
ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.