Create virtual groups for reporting

Virtual groups are used to combine multiple real groups together to create a single group that exists only for the purpose of the current report. Once created, a virtual group can be used throughout the report in exactly the same way that a real group can be used.

Virtual groups are useful in several situations:

Scenarios where there are too few raters in a real group to adequately protect the identity of the raters, multiple groups can be combined into a larger virtual group to better anonymize the data and reach the appropriate privacy thresholds.
Create a Virtual Group to Anonymize Responses with Small Groups

Group	# of Raters
group X	4
group Y	3
group Z	4
virtual group XYZ (group X, group Y, group Z)	11

Scenarios where it is desired that scores from raters in different groups be given the same weight in calculating the overall average score. For example, using real groups to calculate the average score for a question would look like this:
Total Average Score Calculation with Real Groups

Real Group	# of Raters	Total Score	Calculation	Average Score
real group A	5	18	18 / 5 =	3.6
real group B	20	54	54 / 20 =	2.7
real group C	500	2,300	2,300 / 500 =	4.6
Total Avg Score	3 groups	10.9	10.9 / 3 =	3.63

In this situation, group a has significantly more impact on the total average score than group C even though group C has significantly more raters. With a virtual group this bias is eliminated.
Total Average Score Calculation with Virtual Groups

Real Group	# of Raters	Total Score	Calculation	Average Score
real group A	5	18	18 / 5 =	3.6
real group B	20	54	54 / 20 =	2.7
real group C	500	2,300	2,300 / 500 =	4.6
(group A group B group C ) = virtual group 1	(5 20 500) = 525	(18 54 2,300) = 2372	2,372 / 525 =	4.52
Total Avg Score	1 group	4.52	4.52 / 1 =	4.52

The total average score is now much closer to the average score for group C which logically makes much more sense due to the size of group C.