Because creating the Output Report File value can take time, and the amount of time increases as the value of the Analysis Fields and Number of Groups parameters increases, no report is created when you specify more than 15 groups or more than 15 fields. This limit can be altered, however.
To generate a report when you have more than 15 fields for the Analysis Fields parameter value or when you specify more than 15 groups, follow the instructions outlined in the tool documentation. Because creating the report takes time, you can run this tool without creating a report until you decide on a final list of fields. Graphics in the report file are more difficult to interpret when there are lots of groups or many fields.