I have two point layers: one shows the number of people in a county, the other shows the number of people who receive a particular service in that county.
I am symbolizing them both as "proportional symbols", that is, as dots of varying sizes.
However, the scale is different between them, so I can't compare the dot sizes in a meaningful way. 1000 people in one layer is a dot that looks five times bigger than 1000 people in the other. I'd like them both to be symbolized with the same scale so I can see how many people receive services relative to the whole population. Below is a snapshot so you can see what I mean.