I am developing a report that summarises learners attendance and my column group is the week number and underneath that is the date/time of the week. The attendance can then be drilled into. However when the groups are hidden and we are looking at a certain week I would like one of two options:- The expression to display the MODE of the attendance marks within that week (i.e. the most commonly occuring mark, this is a string so I can't use average), this will mean that when drilled down it will simply always show the most commonly referring mark and when at the detail level it will show the actual mark used. THe expression have two options (controlled by an IIF), the IIF being based on wether the group has been drilled into/its visibility property Any suggestions are very welcome!