For each club, I took their club coefficient and subtracted the average of the club coefficients of their three opponents. A positive number means the club has a higher club coefficient than the average club coefficient of their three opponents and a negative number means the club has a lower club coefficient than the average club coefficient of their three opponents. In 2015-2016, the correlation between the difficulty for each club calculated this way and how many points the club got in the Group Stage was .7099. The correlation between club coefficient and how many points the club got in the Group Stage was .6966, so my method was a slightly better predictor than just going by club coefficients without considering the difficulty of the opponents. Here are the 2016-2017 Group Stage difficulties ranked from easiest to hardest: 1. Real Madrid: 112.925 2. Barcelona: 98.558 3. Bayern Munich: 92.045 4. Atletico Madrid: 66.854 5. Porto: 64.957 6. Benfica: 52.955 7. Juventus: 45.598 8. Paris Saint-Germain: 39.670 9. Bayer Leverkusen: 35.861 10. Sevilla: 30.338 11. Arsenal: 29.946 12. Borussia Dortmund: 24.782 13. Manchester City: 18.710 14. Napoli: 17.583 15. Tottenham: 16.156 16. Basel: 6.612 17. Club Brugge: -1.197 18. Lyon: -13.119 19. Dinamo Kiev: -14.565 20. CSKA Moscow: -17.897 21. FC Copenhagen: -25.571 22. AS Monaco: -34.120 23. Leicester City: -38.189 24. PSV Eindhoven: -49.186 25. Sporting Lisbon: -53.110 26. Besiktas: -55.973 27. Borussia Monchengladbach: -57.584 28. Celtic: -59.684 29. Dinamo Zagreb: -62.818 30. Ludogorets Razgrad: -76.228 31. Legia Warsaw: -84.598 32. Rostov: -109.714