I have a requirement for an SSRS report to dynamically change the category of a bar chart based on levels in an SSAS hierarchy. So when a user selects a level from a parameter, the bar chart category needs to change the category group expression to use a different fields in the SSAS dataset. We are trying to keep all of our datasets simple by using the SSAS dataset query designer as opposed to writing MDX. With that, the attribute levels returned in the dataset must remain fixed. This means when the chart category expression changes to a different column/level in the dataset, we must use the aggregate function for the chart values. This all sounded good until the report is run. Since the category group expression is using a conditional expression to dynamically set the category group value, the aggregate function is expecting the scope parameter set explicitly. Setting the scope parameter to the dataset name forces the dataset to only return a single aggregate value from the query so the category values in the chart are all the same value. Hopefully I've explained this well enough. What suggestions are there to solve the problem of dynamic chart categories with an SSAS dataset using the query designer. I appreciate the help in advance.Jeff T Jones