Hierarchical models, or multilevel models, are used to represent data that might vary on, you guessed, different levels. Michael Freeman, from the University of Washington Information School, provides an introduction to the method using a scrolling format. The transitions give a good sense of how the model can change, depending on your approach.
Visual explainer for hierarchical modeling
Divorce and Occupation
Some jobs tend towards higher divorce rates. Some towards lower. Salary also probably plays a role.
Unemployment in America, Mapped Over Time
Watch the regional changes across the country from 1990 to 2016.
People get married at various ages, but there are definite trends that vary across demographic groups. What do these trends look like?