Effect of club reputation match ups on shots on target. For example, the upper left cell of the plot shows the average shots on target when a 20 reputation club plays at home to a 12 reputation club.
The main point to note is that teams playing away to high reputation sides (reputation > 15) get very few shots on target. This means an increased chance of clean sheets for the high reputation home side and a decreased chance of goals for the low reputation sides playing away.
Special thanks to ffscout_luke for sharing the data on club reputation. The club reputation values are those given at the start of the season.