It’s Big, It’s Heavy, It’s Wood: When Log Scales Are All Right

Posted on 2 CommentsPosted in Today I Learned

What rolls down stairs Alone or in pairs, Rolls over your neighbor’s dog? What’s great for a snack And fits on your back? It’s log, log, log!   I’m known for tenuous analogies, so I won’t spend too much time defending the connection between the classic song from TV’s Ren & Stimpy and the logarithmic axis on charts. Except to say this: like a heavy log, this brute force tool is rarely the appropriate weapon of choice for representing a numeric range. A couple of weeks ago, Andy Cotgreave explored the notion of a logarithmic axis on one of his Makeover Monday vizzes. In this case he was attempting to deal with the vast difference between soccer (née “football”) salaries between the highest English league and other, lower divisions. His attempt (click to read his original article): As Andy notes in his post, the logarithmic scale doesn’t fix the problem of range in this view: The default scale slope (on the left) makes all the lines appear as if they start from the same point. I tried a log scale which fixes it, but I think log scales are misleading for many viewers, who either don’t understand what they show, […]

The Second Principle of Calcs: Logic

Posted on Leave a commentPosted in Calculation Lessons

In my last article we talked about aggregation. This is the most important principle of calculations in Tableau. As you’ll see, aggregation affects every other concept in calculations. Want to understand Table Calculations or LODs? You’d better damn well understand how Tableau aggregates data. But those are topics for a future post. You aren’t ready. Today we’re going to discuss logic and how it impacts calculations in Tableau. What Does Logic Mean When You’re Writing Calculations? “Logic” is a very abstract, nebulous term. I am being intentionally vague right now. We are not going to cover the difficult, theoretical concept of logic that you may have taken a course on during the process of obtaining your liberal arts degree. Though as a holder of a liberal arts degree myself the concept is intriguing. We are going to talk about using logic as part of your calculations in Tableau. And I know you will be surprised to hear this but logic in Tableau has a great deal to do with aggregation. Crack open the Tableau calculated field dialog box and filter the syntax to “Logical” and you’ll see this: This window is full of logical operators like “If” “And” and “Then” […]

Makeover Monday: Viz-Off

Posted on 1 CommentPosted in Makeover Monday, Viz Review

This week Wilson and I decided to both try our hand with the Makeover Monday challenge and compare notes afterward. We were sitting in Tableau’s New York office and decided to both start around the same time, cutting off our efforts after an hour. Even though it wasn’t intended to be a competitive exercise we are always trying to one up each other a bit so it was fun to trash talk as we created our respective vizzes. He didn’t tell me this until afterward, but Wilson cheated and started an hour before talking to me about it. This week’s viz comes from Andy Cotgreave before he was famous. Andy published this viz based on Guardian data from 2001-2007: What works: This is a very straightforward approach, with appropriate views to easily interpret the data. The major details stand out and it passes the “5-second test” of knowing exactly what the viz is about very quickly. It’s also easy to rank/sort the information dynamically. What needs some work: It isn’t very engaging. If the point of a dashboard like this is to quickly analyze and come away with facts, this viz nails it. But it’s not going to compel a […]

Podcast: Dashboards and B.I.

Posted on Leave a commentPosted in Podcasts

I play on a soccer team here in New York. One night after a game I went out for a beer with a few of my teammates and one of them asked what I did for a living. Some people know what presales engineers do and some don’t, so usually when someone asks me that question I say “I work for a company called Tableau. We make data analysis software.” I don’t like to say “visualization software” because I think we do a lot more than just data visualization. And I don’t like to say Business Intelligence because I don’t really like the term. But most people know what data is and have some understanding of Excel or general data analysis concepts. This guy, however, responded with, “what, like Dashboards?” That’s a tricky question, even though he didn’t intend it to be one. Because if a customer asked me that question, or someone who was interested in Tableau’s place in the competitive market, I would say “no you idiot! Not just dashboards! Analysis! Storytelling! Actually getting insights from your data! Not those stupid gauge-based reports you think help you monitor your business!” but really this guy was just trying to […]

Tableau Calculations: The Most Important Principle

Posted on 1 CommentPosted in Calculation Lessons

On our recent podcast Wilson and I alluded to a curriculum for someone looking to understand Tableau’s calculations more fully. We agreed that the first step was an understanding of how data can be aggregated. Here is lesson one. Aggregation and Tables People who have worked with databases extensively have an innate knowledge of this but the great thing about Tableau is that you don’t have to have DBA experience in order to understand it. So sometimes it’s important to go back to basics and really make sure really know what you’re doing when you aggregate data. Tableau works with tables of data like this*: *Actually, Tableau deals with lots of types of data sources. Excel tables look like this, but databases are often made up of lots of tables you have to combine. And some data sources like Hadoop don’t store data in tables at all. But regardless, Tableau uses some process to turn data into a table behind the scenes. When you drag and drop a measure in Tableau (in this case, Sales Amount is our measure), it is automatically aggregated. The default is as a sum. Other aggregations are Averages, Minimums, Maximums, Standard Deviations, etc. These are […]

Makeover Thursday: Football Salaries

Posted on Leave a commentPosted in Makeover Monday

I was a little busy earlier this week but I finally got to Andy Kriebel’s Makeover Monday challenge. Here’s the original article, from the Mail Online. There are a few visualizations in the piece, but I’m focusing on the first one. This one: What works: Ugh. Not much. The color consistency helps the viewer draw parallels between the levels of different leagues, even though the names of the leagues have changed. A lot of people hate donut charts but I kind of like the idea that you can throw a nice big label in the middle of a pie chart for better use of space. It’s not terribly hard to make the important comparison (1985 Division 1 wages vs 2015 Premier League wages) because the difference is so vast. What doesn’t work: It’s pretty hard to tell how different the numbers are, and virtually impossible with the lower leagues. The colors are too similar to quickly know which shade of blue corresponds to which league. It’s hard to tell what the “Avg Income” refers to. Most importantly: Even if you are a fan of pie charts, a pie chart makes absolutely no sense here! Pie charts are for comparing percentages […]