Now through Week 5 of the 2019 NFL season, we at PFF have updated our power rankings using PFFELO. The top-10 has shifted significantly, welcoming a slew of thriving NFC teams. On the other hand, not much has changed at the very bottom of the NFL; the four worst teams in the league are pretty cut and dry.
Like any ELO system, it adjusts the ranking of a team after each game based on what happened in the game and the perceived strengths of the team and its opponent prior to the game.