Like Salary, Effective Experience also follows the 1.5x exponential rule. Hence, gaining effective experience for higher levels takes more time and becomes increasingly difficult. Often, once a SWE reaches a certain level, the new skills they learn are barely sufficient to compensate for old skills that have become obsolete. The SWE’s effective experience remains constant, and they remain at the same level.

How come an “Entry Level” SWE has 4.5 years of experience? Because they already should have acquired a range of skills from University, School and Coding Projects relevant to the SWE role. “Work” is not the only means of “effective experience”.

Finally, where do you get 77 years of effective experience? You either live (and work) till you’ve passed a 100, or you are a genius who can acquire several years of effective experience every raw calendar year. Both are highly unlikely, and, not surprisingly, there are almost no Fellows at Google or E10s at Facebook.

Concluding Thoughts

So “What’s the difference between a “Software Engineer” and a “Senior Software Engineer?” It is difficult to say, merely based on titles. But a combination of Levels, Salary and Effective Experience, will give you a better picture.