It would be very useful to be able to compute a weighted average in the Operations Dashboard. This would allow the calculation of rates across geographies. Furthermore, a dynamic weighted average should be able to respond to a filter. For example, if I have four police districts, I could calculate a crime rate for the whole city, or for a subset of districts. Then, I could filter to crimes where the victim is a certain sex - the numerator and denominator both have to change to get the correct crime rate.
A dynamic filter could be achieved easily by having a "weight" option in the element configuration panel for elements like serial chart, pie chart, indicator, or gauge.. Ideally you could weight by a field in the same layer or by a field in another layer.