I often write in my notes that goal difference is a good indicator of the true underlying ability of a team and one you can make with a quick glance at a league table. It is not foolproof but has stood the test of time and is a good place to start your analysis, especially at the beginning of a new season and doubly so in the EPL and EFL where games are so competitive and also where teams are playing 38-46 rounds, so a pretty big sample.