The Webform module will provide you with an analysis of each and every field that users may (or may not) enter data in.  To view this information, do the following:

  1. From the Webform Manager, click on the Analysis link, or if you're inside a webform, click on the Analysis tab:
  2. Included in the Analysis results are the following:
    • A simplified view of fields that gives focus to calculable fields
    • An Add analysis components fieldset that allows you the ability to add additional fields for analysis