by Brina Dec. 26, 2018

If you click on an individual gymnast’s page, you might notice something new at the top: consistency stats!

The consistency stats are a metric that I came up with to put a number to our general intuition about a gymnast’s consistency. The most important thing to know is that **a lower consistency stat indicates a more consistent gymnast**.

Here’s where the numbers for each gymnast come from.

**For each score, subtract the d-score from the total score, leaving the e-score minus any neutral deductions.**

This gets at what we’re interested in when we talk about consistency: how well did the gymnast hit? The difficulty that a gymnast choses to compete on any given day shouldn’t impact her consistency stat - except through its impact on her execution.**Calculate the standard deviation of the scores we calculated above score on each event.**

The standard deviation measures of how spread out values are. This is why a lower consistency stat indicates a more consistent gymnast; a zero is a “perfect” score. Calculating standard deviations separately on each event ensures that a gymnast doesn’t look inconsistent just because there’s a lot of spread between her beam execution and her vault execution - that’s just a feature of the code of points.**Take the mean of the standard deviations for each event.**

This gives us the “overall” consistency score listed in the rightmost column of each table.

I wrote a bit about the thought process behind this measure a while back, so check out that post if you want to know more about the origins.

**How exactly do I interpret the numbers themselves?**

Let’s take a gymnast with a balance beam consistency stat of 0.5. This means that each of her e-scores on beam is, on average, 0.5 points higher or lower than her mean beam e-score.

**What time period do these statistics account for?**

The consistency stats pull data from the past year - that is, 365 days before today. They’ll update automatically every time you visit a gymnast’s page, so if you go back to a page next month and the stats have changed, it’s probably because some old scores dropped out of the calculation or some new ones were added in.

**Is every score from the past year included in the calculation?**

I can only include scores for which I have separate d-score information. I get all of my score data from TheGymternet, and they do a really great job of tracking down scores— so when I don’t have d-score information for a meet, it usually means that score just isn’t online. If you scroll down to the bottom of each gymnast’s page, you’ll see the data we have on d-scores.

**Why doesn’t every gymnast have a consistency stat on every event?**

A gymnast must have competed an event at least *twice* in the past year in order to receive a consistency score. If a gymnast only competes once, then we have no way of knowing how consistent she is. And even if she’s competed twice, I might not have d-scores for both competitions.

**What do you do with second vault scores?**

If a gymnast competes a second vault, then you’ll see her consistency stat on those vaults alone in the “VT2” column of her page. However, in calculating her overall consistency score, I simply average the stats for her first vaults, bars, beam, and floor - ignoring the second vaults. Consistency is often relevant for team or all-around competitions, so this number is a little more useful.

**Why don’t you publish a consistency ranking?**

The more you compete, the more different scores go into the ranking, and the harder it is to get a nice low consistency stat. This means that the rankings would basically always be topped by gymnasts who’ve competed twice on one event in the past year. I firmly believe you should look at the consistency stats in context - that’s why they’re on each gymnast’s page right on top of the full list of that gymnast’s scores. If we just looked at the numbers on their own, we’d lose track of what goes in to the consistency stats.

**This gymnast never seems to hit. Why are her consistency stats so good?**

Consistency stats measure whether a gymnast performs at the same level every time she goes out. A gymnast who always falls in the exact same spot on her bar routine is therefore very consistent - even though she’s not hitting. Consistency stats are a guide to how much future scores might look like past scores; they don’t necessarily indicate how well a gymnast is going to do.

**That stat looks weird. It’s totally off with my intuition about how this gymnast does.**

I’m not surprised at all! The consistency stats are a very specific metric based on the limited information that comes from scores; there’s a lot more that goes into your impression of a gymnast! But as always, if you think there’s a bug, please e-mail me at brina.scoreforsore@gmail.com.

Got more questions? Comment below and I’ll get back to you!

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