This is a very common question we receive.
By default, Cubeyou orders charts by Affinity, unless you are looking at demographics for states, which is first filtered by highest percentage of Reach as show in figure 1 below:
When first looking at the data, keep a good balance between the reach and affinity. For example, first take a look at what is over-indexing for your target as shown in Figure 2. below:
In the case of state demographics, focus on the top states by reach but prioritize the ones with the highest affinity, so this way you have a good compromise on quality over quantity; not just shooting for the mass percentage. Particularly with states, it is best to look at affinity since bigger states tend to show a higher percentage of reach because of sheer population size.
To summarize, the best practice is to have a balance between the two indexes Reach and Affinity, to see the best representation of the data.