First Touch Attribution

The initial UTMs are saved against the customer when they register and these values are never changed. This works great for reporting on acquisition campaigns. This is called “First touch attribution”.

Last Touch Attribution

With last touch attribution, UTMs are typically captured once per session and this happens when the user loads your site while UTMs are present in the URL. Subsequent events are also attributed to these UTMs.

Lookback Windows

Amplitude graphs have a lookback window of 12 months when using the Daily filter. If you change the filter to Monthly or Quarterly, you can look back for up to 3 years. Note that you will only be able to see data from the date that Amplitude was enabled on your instance and onwards.

Refresh

If you notice a discrepancy in the number of events in an Amplitude graph, it’s helpful to remember that Amplitude has a caching mechanism.

The cache time is dependent on the time interval (daily, weekly, monthly) and the number of days from the present day. You can force update the chart by clicking the Refresh button. This will add the last data point to include new events.