The ability to view a factor report or symtom correlations from data within a time range, discounting data outside that range. Perhaps with the ability to export that time frame report?

For example, if someone was taking a new medication for only a week and wanted to see the effect that had on their symptoms (potentially with new symptoms) without the several months of symptoms preceeding that. If a new symptom appears that was not present before, the factor report is going to say there is a +1200% effect.