The study looked at how different regions in Turkey were getting closer or farther apart economically between 2004 and 2011. They found that during economic downturns, the income gap between regions decreased, but during economic upswings, it increased. The researchers used different methods to show that regions with lower incomes were catching up to those with higher incomes over time. They also discovered that the way regions are geographically connected affects how their incomes change over time.