# TRIX-y Tennis Players

I am not the most chart-oriented person. I see a lot of graphics on sports analytics blogs that I drool over from an aesthetic perspective, but my mind is not geared to get much information out of them. It’s not their fault. I always turn to the text.

It is therefore surprising (at least to me) that I’m posting something that is mostly graphics, and therefore mostly-not text. Maybe it’s because I have divided my time this morning between looking at US stock prices and writing about linear regression, and I just need something lighter.

If you follow financial markets, you probably know there are all kinds of formulae and indicators to show price trends and momentum. One of those is called the TRIX. The TRIX is a triple-smoothed exponential average of stock prices. Huh? Basically, you take a weighted average of stock prices for a particular day (financial people call it an exponential moving average, or EMA). Then you take the weighted average of the first weighted average for the same number of days to get a “double smoothed” average. Then you take the weighted average of the second weighted average for the same number of days. The TRIX is the percentage change in the third, or “triple-smoothed,” average from day-to-day.

For absolutely no good reason whatsoever, I calculated the TRIX on the Dominance Ratios of Roger Federer, Rafael Nadal, Novak Djokovic and Alexander Zverev in their non-Davis Cup matches since the start of the 2018 season, and put them in line charts. The single EMA is too volatile to include, but on each of these charts, the red line is the double-smoothed average, the green line is the triple-smoothed average, and the purple line is the TRIX. I used a five match period for the EMAs, so the TRIX is the one-*match* percentage change in the triple-smoothed average.

So here you go. While you look at these, I’m going to send a note to TD Ameritrade to include Dominance Ratio TRIX in their ThinkorSwim software platform.