Kevin Rudy

I write about how statistics can be used to help understand sports, but these techniques and tools have applications in quality improvement and any other endeavor that involves the analysis of data. Continue Reading »

Variance is a measure of how much the data are scattered about their mean. Usually we want to minimize it as much as possible. A manufacturer of screws wants to minimize the variation in the length of the screws. A restaurant owner doesn't want the taste of the same meal to vary from one day to the next. And they might not know it, but most football coaches choose a low variance strategy when they... Continue Reading
In 2007, the Crayola crayon company encountered a problem. Labels were coming off of their crayons. Up to that point, Crayola had done little to implement data-driven methodology into the process of manufacturing their crayons. But that was about to change. An elementary data analysis showed that the adhesive didn’t consistently set properly when the labels were dry. Misting crayons as they went... Continue Reading

7 Deadly Statistical Sins Even the Experts Make

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Imagine a multi-million dollar company that released a product without knowing the probability that it will fail after a certain amount of time. “We offer a 2 year warranty, but we have no idea what percentage of our products fail before 2 years.” Crazy, right? Anybody who wanted to ensure the quality of their product would perform a statistical analysis to look at the reliability and survival of... Continue Reading
If you want to use data to predict the impact of different variables, whether it's for business or some personal interest, you need to create a model based on the best information you have at your disposal. In this post and subsequent posts throughout the football season, I'm going to share how I've been developing and applying a model for predicting the outcomes of 4th down decisions in Big... Continue Reading
Down 7-0 midway through the 1st quarter of the College Football Playoff National Championship game, Ohio State was facing a 4th and 2 at the Oregon 35 yard line. Buckeye coach Urban Meyer had a decision to make. Attempt a 52 yard field goal, punt and try to pin Oregon deep inside their own territory, or attempt to gain the 2 yards and get a fresh set of downs. Meyer decided to go for it. Ohio... Continue Reading
With their victory in game 6 over the Tampa Bay Lightning, the Chicago Blackhawks won their 3rd Stanley Cup Championship in the last 6 years. This is an incredible feat that no doubt means the Blackhawks have been a very talented hockey team over that stretch. But just like random variation can play a part in quality processes, luck can play a part in sporting outcomes. So how lucky has... Continue Reading
  The NFL recently announced that after scoring a touchdown, teams will be required to kick the extra point from the 15 yard line as opposed to the 2 yard line. This is a pretty big change. And whether you’re trying to improve the quality of your process, or simply trying to make a sporting event more exciting, it’s always good to know what kind of effects your change will have. So I’m going to use... Continue Reading
The NBA playoffs are under way, and all eyes are on LeBron James to see if he can finally bring a championship to Cleveland. But one could argue that there is even a bigger storyline going on: whether Tim Duncan can equal Michael Jordan’s six NBA Championships. Duncan is currently in his 18th season in the NBA, and he is still playing at a very high level. Yet, he’s never in the conversation when... Continue Reading
Are you ready for some madness? Me too! So let’s break down the brackets. I’ll be using the Sagarin Predictor ratings to determine the probability each team has of advancing using a binary logistic model created with Minitab Statistical Software. You can find the details of how the probabilities are being calculated here. Before we start, I’d also like to mention one other set of basketball... Continue Reading
The NCAA Tournament is right around the corner, and you know what that means: It’s time to start thinking about how you’re going to fill out your bracket! For the last two years I’ve used the Sagarin Predictor Ratings to predict the tournament. However, there is a problem with that strategy this year. The old method uses a regression model that calculates the probability one team has of beating... Continue Reading
As I’m sure you’ve heard by now, Kentucky is really good at basketball. They're the only team in the country without a loss, and they have a realistic shot at becoming to first team to win the championship with an undefeated record since the 1976 Indiana Hoosiers. Under any ranking system you want to use, Kentucky is clearly the #1 team in college basketball. Well, almost any ranking system. All... Continue Reading
Over the weekend Penn State men's basketball coach Pat Chambers had some strong words about a foul that went against his team in a 76-73 loss against Maryland. Chambers called it “The worst call I’ve ever seen in my entire life,” and he wasn’t alone in his thinking. Even sports media members with no affiliation to Penn State agreed with him. This wasn't the first time this season Chambers has... Continue Reading
In the past week there has been a big commotion over this article that shows since 2007 the Patriots have fumbled at rate that is extremely lower than the rest of the NFL. Why 2007? Because that’s the year the NFL changed their policies to allow every team to use their own footballs, even when they were playing on the road. So if the Patriots were going to try to gain an advantage by deflating... Continue Reading
Last Friday I had an interesting tweet come across my Twitter feed. And that was before the Patriots failed to cover their first playoff game of 2015 against the Ravens. When you include that, the record becomes 3-11, good for a winning percentage of only 21%! With the Patriots set to play another playoff game against the Colts, it seems like the smart thing to do is to bet the Colts to cover. But... Continue Reading
Throughout the college football season, I’ve been looking at the influence of the preseason AP Poll on rankings later in the season. Each analysis found a positive association between preseason rankings and the current rankings. That is, between top-ranked teams with a similar number of losses, teams ranked higher in the preseason are also ranked higher in current polls. The biggest exception is... Continue Reading
College basketball season tips off today, and for the second straight season Kentucky is the #1 ranked preseason team in the AP poll. Last year Kentucky did not live up to that ranking in the regular season, going 24-10 and earning a lowly 8 seed in the NCAA tournament. But then, in the tournament, they overachieved and made a run all the way to the championship game...before losing... Continue Reading
The college football playoff committee waited until the end of October to release their first top 25 rankings. One of the reasons for waiting so far into the season was that the committee would rank the teams off of actual games and wouldn’t be influenced by preseason rankings. At least, that was the idea. Earlier this year, I found that the final AP poll was correlated with the preseason AP poll.... Continue Reading
A few weeks ago I looked at how the preseason college football poll influences the rankings at the end of the year. I found that for the most part, the teams that ranked higher in the preseason tend to be ranked higher going into the postseason. So if Team A and Team B both finish the regular season undefeated, the team that was ranked higher in the preseason tends to be the one ranked higher... Continue Reading
The no-hitter is one of the most impressive feats in baseball. It’s no easy task to face more than 27 batters without letting one of them get a hit. So naturally, no-hitters don’t occur very often. In fact, since 1900 there has been an average of only about 2 no-hitters per year. But what if you had the opportunity to bet that one wouldn’t occur? That’s exactly what happened to sportswriter C. Trent... Continue Reading
A mere 10 seasons ago, USC and Oklahoma opened the college football season ranked #1 and #2 in the preseason AP Poll and the Coaches Poll. They remained there the entire regular season, as neither lost a game. But as chance would have it, they weren’t the only undefeated teams that year. Both Auburn and Utah went undefeated, but neither could crack the top 2, and Oklahoma and USC went on to play... Continue Reading