Things that are good about expected goals (xG):
- They can help show who deserved to win a match when the score line doesn’t
- They are a step up from using more basic data like shots to analyse team performance and the likelihood of future results
- They help eliminate luck from analysis
- They help us to scrutinise and compare player performance more precisely
Things not so good or limitations of expected goals:
- People watching the match can often deduce what expected goals data does and sometimes more accurately
- The exact expected goal value is down to interpretation and can vary a lot
- The expected goal value can be misleading due to the quality of the players involved in the opportunities
- Game state (e.g. team winning 3-0 at half time) can affect the desire/necessity to create further chances, potentially skewing the overall data