You can utilize an engagement factor to determine the amount of alerts a particular user has submitted.
  1. Select Data Management > Tasks > Task List tab.
  2. Select Create a New Task.
  3. Choose Website Engagement Segmentation.
  4. Enter a name, description, and select which engagement factor field you would like to populate with the data.
  5. Set a weight one of 1 for Alert Responses.
  6. Set how many days you would like to go back.  Ex: Set 30 for the last 30 days.  If this is for an odd amount like Year to Date you can enter any amount of days.
  7. Save once completed.
You will now be sent back to the list of current tasks.  You can set it to run one time, or you can activate to run periodically.  Once the task completes it will populate the field created on each constituent record and you can query on the data.  Example: If you would like to determine how many users have submitted more than 0 alert response in a timeframe: Engagement Factor X is greater than or equal to 1.