Who was truly elite in 2018? Our Dominant 20 answers that by pitting the year's best against their top rivals with cold, hard math.

We started by grading athletes by the strongest performance measures available in their sport over their most recently completed season (except F1 numbers, which are through Nov. 11, and NFL numbers, which are through Nov. 26), including timed scores, earnings and, wherever possible, advanced metrics.

Then, to put those achievements into historical perspective, we compared the top athletes in a sport to the best in their field each year since 1998 and adjusted the results to put those athletes onto one common baseline, yielding our ratings.

So what does Simone Biles' dominance score of 3.25 mean? In 2018, she was 3.25 standard deviations better than the typical top-four performer in all-around women's gymnastics since 1998 -- rendering her the year's most dominant pro athlete.