While I was writing my previous post on goalscoring variances and Pythagorean estimation, I wanted to know if there were some kind of relation between goalscoring variances and the average number of league points taken per game. So I extracted variance data, league points (which I then divided by matches played to get an average number of points per game) from the set of league tables that I have. The scatter plot (again color-coded by average intervals) is below.
There is a fair amount of overlap between regions, but there are some trends that are apparent. First of all, there doesn't seem to be much of a correlation between offensive goal variances and average points won per match, except for perhaps the poorest teams. On the other hand, there does appear to be a correlation between defensive goal variances and average points won per match. The elite clubs — the ones averaging more than two points per match — had very low defensive variances, or to put it another way, a more consistent defensive unit.
So if your team's defense lets in few goals and does so consistently, more often than not your side will be at or near the top of the table. Inconsistent teams, naturally, have more inconsistent results and an uncertain outcome in the table.