The article looks at how people in countries using the euro feel about the currency from 1999 to 2017. The researchers used big sets of data and modern math methods to study this. They found that most citizens in euro countries support the euro. When there's a crisis, support goes down, but when things get better, support goes up. This is true for both big economic factors and personal ones. People with different levels of education and views on their own money situation also have different levels of support for the euro.