What factors have historically affected the homicide rate in the United States, the rise of homicides in 2015?

Public project summary

Homicide in the United States has been trending downwards since at least 1990. 2014 had the lowest homicide rate in 51 years. However 2015 has had an increase in homicide rate by 10.8%. Why did this happen? This research project will attempt to answer that question by analyzing historical data and creating a model to determine what factors affect the homicide rate.