The Fermi Paradox was originally postulated by Enrico Fermi, sitting with a bunch of scientists, he took the number of planets estimated (400 billion) to be in the Galaxy, the average estimated lifetime of those worlds, divided by the estimated time that it took the human race to develop.
Taking this as typical, he suggested that there should be thousands of intelligent civilizations and we should have seen one by now.
“Where is everybody?”
This scientific study postulates that the reason why we have not seen any is that intelligent races have a propensity to self destruct.
“The authors looked at a range of factors presumed to influence the development of intelligent life, such as the prevalence of sunlike stars harboring Earth-like planets; the frequency of deadly, radiation-blasting supernovas; the probability of and time necessary for intelligent life to evolve if conditions are right; and the possible tendency of advanced civilizations to destroy themselves.”
I personally think their work is gratuitous fluff. It answers the riddle of the Fermi Paradox, but we have no way of gathering evidence to prove or disprove it.