I can’t seem to cause my `trackingCallback` to tri...
# ask-questions
I can’t seem to cause my
to trigger. Wouldn’t this cause 2 events to be triggered?
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const GBTest = () => {
  const { value: experiment } = useExperiment({
    key: "new-headline",
    variations: ["Hello", "Hi", "Good Day"],
  const { on: feature } = useFeature('multi_currency');

  return <h1>{experiment} - {Boolean(feature).toString()}</h1>;
It only calls the trackingCallback if the user is included in an experiment. By default, experiments require an attribute
to be specified in the GrowthBook instanced passed to the GrowthBookProvider.
If that attribute is missing, we can't do the random sampling to determine what variation the user is in, so they are excluded from the experiment.
We have a Chrome extension that helps debug features and experiments. It will show you a detailed log of exactly why you are excluded from an experiment. https://chrome.google.com/webstore/detail/growthbook-devtools/opemhndcehfgipokneipaafbglcecjia