As the prison population grows, a rising rate of incarceration feeds small and large businesses such as providers of furniture, transportation, food, clothes and medical services, construction and communication firms. Furthermore, the prison system is the third largest employer in the world. Prison activists who dispute the existence of a prison industrial complex have argued that these parties have a great interest in the expansion of the prison system since their development and prosperity directly depends on the number of inmates. They liken the prison industrial complex to any industry that needs more and more raw materials, prisoners being the material.