This is hard to answer without actually knowing what kind of forms you got, how they are different from each other and what their ultimate goal is.
Another thing to look out for is what type of traffic goes to what page with and without forms. A rolling average may be OK to see a general trend of how your forms perform over time, given that forms don't change, are added or removed from the site.
Without knowing your current scenario, I'd try to come up with a report that includes a little more details:
- Avg. Conversion Rate of all forms, based on Sessions/Uniques to Form Views to Form Completions
- Avg. Conversion Rate of Grouped Forms (Signup Forms, Purchase Forms, Lead Generation Forms, Adress Forms, etc.), based on Sessions/Uniques to Form Views to Form Completions
- Breakdown of all individual Forms, based on Sessions/Uniques to Form Views to Form Completions
This will basically give you two tables like so:
Form, Sessions/Uniques, Formviews, Completed
All, 20/10, 12, 4
Group 1, 20/10, 4, 2
Group 2, 20/10, 4, 0
Individual 1, 20/10, 2, 2
Individual 2, 20/10, 2, 0
Now you do have some more insight into what forms perform how well with how much traffic.
See that individual form number 1? That one has a conversion rate of 100% while number 2 has a conversion rate of 0%. Some grouped forms have 50% CR and some other have 0% as well. The average has 33% CR.
So in reality, you average is a good to know KPI over time. It will not show you where your superstar forms are, how good they are doing and what you need to do to affect that average.
Your report could look like this:
Traffic to Form (S): 60%
Traffic to Form (U): 120%
Form to Completion: 33%
Session to Completion: 20%
Uniques to Completion: 40%