If you were to ask random Americans what income class they fall into, there’s a good chance they’ll say “middle class”, regardless of how much money they make. It stands to reason, then, that a change in their family’s situation, like a lost job or a new higher-paying one, is unlikely to change their perceptions on their social class. This is particularly true because, for many people, the “middle class” is just as much about your education, job, resources, and aspirations as it is about your paycheck.
Let’s follow 11,172 families that spent at least one year in the middle class between 1968 and 2018 to see if they actually remain in the middle over that 50 year period.
Calculating “Middle Income”
To understand movement between social classes, we need a quantitative metric: something we can measure to define the middle class. Many researchers use household income and thus numerically locate the families that are in the middle of the income distribution. Even then, there are many ways to numerically define the “middle” of an income range. One technique is to use the mathematical concept of quintiles, which requires equally dividing up the entire population into five groups based on their income. Here’s how the concept of quintiles works:
STEP 1
Collect annual household income data from all families
STEP 2
Sort all families in order of lowest household income to highest
STEP 3
Separate families into 5 groups with the same number of families in each group. These are called quintiles. Families in the 3rd or middle quintile can be thought of as being “middle income”. For our essay, we consider “middle income” families to be the “middle class” and will use the two terms interchangeably.
Moving Quintiles
Now that you’ve gotten a primer on what quintiles are, we want to know how much you think our middle income families' economic quintiles have changed over the past 50 years. This is called economic mobility, and it refers to the ability for individuals or families to move between income quantiles.
So let’s see what you think. Have these middle income families stayed pretty close to the middle, moving only one quintile to upper-middle or lower-middle income levels or quintiles? Or do you think they have spent time in other social classes as well, perhaps even making their way from the lower class to the upper (or vice versa)? Tell us what you think.
