[brianwawok]

So you double in skill. Can you double your rate? Maybe maybe not. But if you are bid per project you can surely double your clients.

[imaginenore]

There are only that many hours in a day. Doubling your skill doesn't double your speed.

[brianwawok]

I don't even know what double skill means. What is a skill of 5 vs 10?

The point is as you get better, you can MORE THAN double your rate at solving problems. A junior programmer might spend a week writing a way to sort a list. A senior programmer might call Arrays.sort and be done in 30 seconds.

[dexterdog]

Doubling your skill (and experience) can quadruple your speed.