The authors decided to compare these periods of increased shootings with the unemployment rate because unemployment is an aggregate statistic that summarizes many economic hardships. Unemployment may summarize the hardships faced by students’ families, as well problems that older students face as they make the school-to-work transition. Strong evidence in the literature also suggests that children feel the impact of their parent’s employment status.
The authors suspected that gun violence in schools may be linked to students’ disappointment in previously held beliefs that education can improve economic opportunities. If students begin to feel that education won’t help them find economic security, perhaps this makes them more likely to lash out within the educational institution that is failing them.
In this investigation, the authors found a significant relationship between the number of shooting incidents per month and the unemployment rate. Increasing unemployment was strongly associated with decreasing time between shooting events. The authors also looked at the relationship in reverse and checked to see if times with higher shooting rates also had higher rates of unemployment. They found that months with two or more shooting events had larger mean-normalized unemployment rates.
И результаты, и выводы вполне ожидаемы.