Advanced Baseline: Projecting the 2018 WTA leaders ... sort of

In the last article, I applied some crude aging curves to the current ATP leader board to project where they all might be over the next five years. The next logical step is to apply the same methodology to the women’s players. Here are the results of the same method applied to the current women’s leaders and a representative sample of the youth movement:

This didn’t turn out the way I’d hoped at all. It basically shows no predictable movement between players for the next five years.

I certainly don’t think Serena will keep up her current pace for five years.

The reason why the graph turned out this way is pretty simple to explain:

Not only is this approach really unsatisfying, it also leaves more questions than answers.

Why are there no clay-courters outside of Sara Errani at the top of the women’s board? What does the historical clay/hard-courter distribution look like at the top, and how hard-skewed is the current leaderboard compared to historical average? Do hard-courters really have no predictable age movement over time?

And if surfaces can’t tell us how players will age, what will?

Over time, there will be better approaches than the simple method I’ve outlined above. But I’m just as interested in why certain projection methods work well on the men’s tour but not on the women’s. Using surfaces to generate aging curves definitely has its limits, but it’s still a useful starting point for generating more robust curves in the future.