[news_to_me]

Ok, but seniority is still the independent variable in all those graphs, so it belongs on the x-axis.

[dragonwriter]

No, seniority is the dependent variable. The other factors determine seniority, not vice versa.

[akavi]

The article uses phrases like "As a developer become more senior, they become more independent.", which indicates they view seniority as the independent variable.

[yowlingcat]

Yeah, it looks like seniority is the dependent variable. It also looks like it's the monotonically increasing variable. Seems like it should be on the X axis.