Two years ago [I moved to the United States](https://money.stackexchange.com/q/46018/1088) and got a brand-new, never-used social security number. I started with a blank slate. I have read "[How much does credit score matter](https://money.stackexchange.com/questions/59243/how-much-does-credit-score-matter)" and I've read "[What is a good credit score](http://www.creditscoring.com/pages/bar.htm)" referenced on that question.

Since then, I've only done two credit-related things:

* In December 2015 I leased a mid-range car on a 2-year lease. I paid a higher than typical monthly payment due to my non-existing credit history, but I have never missed a single payment.
* In early 2017 I tried my luck on an American Express platinum card and was approved immediately. I've never had any relationship with Amex before the application, and I did not lie to any question (of which there was only "Name, Address, SSN, total income").

I do not carry any credit cards or loans (the Amex is a charge card and I pay it in full twice a month). Credit Karma is telling me I have a credit score of 655 (TransUnion and Equifax), American Express is telling me I have a score of 716 (Fico). These two numbers are wildly different.

This seems to be telling me that:

* Getting a positive credit rating is quite simple
* Income is more important than credit. According to Credit Karma, only 14% of people with an American Express Platinum have a score equal or lower than mine -
but Amex gave one to me anyway.
* There is a an element of randomness in how credit scores are reported and used

Are these assumptions correct? Or have I just been lucky?