Sparklines Archives | XLCubed Blog

Bandlines in XLCubed

XLCubed/ 25th January 20134th January 2019/ Charting & Visualisation

In early January this year Stephen Few introduced the concept of Bandlines. He identified a useful extension to Sparklines, making use of shaded or coloured horizontal bands to provide more information on the context of the trend line itself. See Stephen’s article on Bandlines and the thinking behind them for a detail description.

The Sparklines are ideal for showing individual trends in a small amount of screen real estate, and we use them extensively in dashboards, typically in a ‘visual table’. By definition Sparklines are small, and to make the trend easily readable, they are typically scaled individually so that each Sparkline uses the whole vertical axis. This means they do not give any impression of the scale of the numbers involved across different rows. It’s possible to use a common scale, and while sometimes that works more often it means many of the rows with smaller values are excessively flattened.

Bandlines address this by introducing horizontal shaded areas depicting the lower, middle and upper quartiles and the median represented by a line. The user can determine the context of the bands. The two most common examples would be plotting recent trend in the context of a longer period, or plotting individual rows in the context of the overall set of data being displayed.

We think Bandlines add real value, so hats off once again to Stephen, and we’re pleased to say that Bandlines are now available in the current version of XLCubed (see here for more detail).

The screenshots below show two examples, displayed in two colour schemes.

The charts depict historic margin by store. The ‘Banding across all stores’ charts show the 30-day trend for the individual store, set in the quartile context of the data for all 11 stores in the table. We can see that for the Gilroy store in row 1, while the margin has varied, it remained in the top quartile when set against all stores for almost the whole period.

The ‘Banding by store, 90 days’ charts show the individual 30 day trend, set in the context of the previous 90 days for the individual store. This helps provide much more historical context, but the line itself still focuses on the more recent trend. Stockton is probably most noteworty here as across the 30 day period it has dropped from the top quartile into the 1st quartile across the whole 90 day period.

We’d love to hear your thoughts (and also which colour scheme works best!), we will also be adding Sparkstrips in the near future so watch this space.

Excel Dashboard Competition: Bank Dashboard

XLCubed/ 11th August 200810th January 2019/ Dashboard Design

This blog post is the first in a series of blog post that features the winners of the 2008 Excel dashboard competition.

“A dashboard is a visual display of the most important information needed to achieve one or more objectives; consolidated and arranged on a single screen so the information can be monitored at a glance.”
—Stephen Few, Information Dashboard Design (2006)

The dashboards were judged on the clarity and effectiveness of their design, particularly

Clean and clear organization
Effective table and chart design
A single-screen display, properly designed for the web, screen or print outs

Furthermore we honored the technical aspects of the dashboard, did it use effective (Excel) techniques for

The Dashboard layout
Data management, pulling data from a database or data warehouses
Data logic and calculation : YTD figures, variances, etc….
Dashboard delivery: Sharing the dashboard via PDF, the web or as an Excel Workbook

Today we will review the winning entry, Wades Stokes Bank Dashboard:

Continue reading “Excel Dashboard Competition: Bank Dashboard”

Graphical Table – Abortion Data 1980 – 2003

XLCubed/ 22nd July 200815th February 2021/ Charting & Visualisation

Here’s the history of the Abortion data set

1) Jorge used some U.S. Census Bureau data (original Excel file) to visualize the abortion ratio as a small multiples chart,

2) In Small Multiples – Abortion Data 1980-2003, I have written about Jorge’s panel chart. I like the panel (small multiples) chart, but felt that it can be improved.

3) Jon Peltier posted on Re: Abortion Ratios 1980-2003 and Interactive Multiple Line Chart some nice Excel techniques to create interactive charts to analyze the Abortion data set.

Here is a different view on the data set as a Graphical Table using MicroCharts. The Graphical Table is a hybrid between the panel (small multiples) chart and a plain table of numbers. It nicely integrates the numbers with small charts, so-called sparklines, in a table. The sparklines show you the trend of the abortions over the years and the in-cell bar charts give you a feel for the distribution over the age groups:

Graphical Tables – An Alternative to Treemaps

XLCubed/ 11th June 200810th January 2019/ Charting & Visualisation, Grid & Report Formatting

Sean blogged the other day about using a treemap to visualize the drivers of the Australian Inflation. He got inspired to create a treemap by an NYT article that used an interactive version of the following treemap:

This chart looks nice on the first view. It makes nice use of muted colors, the shapes look well balanced and certainly the graphic designer did a good job. However, from a data visualization perspective this chart has a couple of flaws.

Ben Shneiderman designed Treemaps to visualize deep directory tree structures.

Ben explained treemaps in an article as:

“Among the growing family of visual analytic tools, treemap are flourishing in organizations that require daily monitoring of complex activities with thousands of products, projects, or salespeople. Tabular reports, bar charts, line graphs, and scattergrams are important tools, but for complex activities where there are numerous sales regions, manufacturing plants, or product lines the hierarchical structures provided by treemaps can be helpful. While tabular displays and spreadsheets can show 30-60 rows at a time on typical displays, the colorful presentations in treemaps can accommodate hundreds or thousands of items in a meaningfully organized display that allows patterns and exceptions to be spotted in seconds.[…] Treemaps are a space-filling approach to showing hierarchies in which the rectangular screen space is divided into regions, and then each region is divided again for each level in the hierarchy.”

The first problem the NYT chart has is that it does not visualize the hierarchy as rectangular areas. The inflation drivers are visualized as asymmetric round shapes. It is difficult to compare the relative size of rectangular shapes but it gets almost impossible for asymmetric shapes. Also does this treemap lack labels for the smaller inflation drivers.

Sean published in his blog post a treemap which does not have the problems mentioned above:

Ben designed treemaps to visualize thousands of regions, products, etc ; but the Inflation chart only comprises 20 Inflation Drivers grouped into 7 categories. A simple sorted table would do a better job communicating the numbers as Kaiser Fung from Junk Junks wrote in his post.

Inspired by this post and my comment Sean came up with this graphical sparkline table designed with Excel and MicroCharts.

This is already quite an improvement on the treemap, as we can see increasing and decreasing inflation trends and sparklines rather than traffic light colors as in the tree map version. Also it is much easier to read for non expert users.

Some minor things we can improve in Sean’s chart are:

We can sort the inflation drivers by Weight, to have the most important ones at the top
Changing the area to the sparkline puts emphasis on the trend rather than the absolute value of the values (as the area chart does)
Inline deviation charts allow us to visualize the MoM and YoY % changes

Small charts are beautiful

XLCubed/ 8th May 200810th January 2019/ Charting & Visualisation

Well, since you are reading this, I’ll assume that you took the red pill, so let’s keep moving and find out how deep the rabbit hole goes.

We saw that people usually design charts larger than they need to be. Why? Is it because we can’t fit the data into a smaller space? No, it isn’t. It is because in smaller charts there is no room for non-data elements, like title, legend, grid lines. In the dominant “Excel chart defaults” school of thinking data is not a priority.

This is a simple exercise that you can try safely at home and demonstrates it clearly. Start by creating a line chart in Excel, like this one:

You can see the data, right? Now make the chart smaller:

Here is a fierce territorial competition, and guess who’s winning? Make the chart a little smaller:

The title and the legend win, as usual. The data must be here somewhere, but who cares?

This chart size is not large enough. Or so it seems. But what happens when we remove some non-data elements? Since we don’t need the legend, and we can put the title somewhere else, we can remove both:

We are getting our data back! Let’s just leave the data and a simple grid line:

I used MicroCharts to display the same data using both a line and a column chart:

With MicroCharts, you can add a “normal band” or a reference line that helps you to understand how the data departs from the expected values.

The above charts show percentage change on previous period GDP at market prices in the US (1980-2009). Here is the same data for some selected countries in the EU:

Michelangelo said: “I saw the angel in the marble and carved until I set him free“. Like him, keep carving your chart until you set your data free. The essence of a chart is the patterns you discover, buried under all the junk. By making your charts smaller you are force to remove that junk.

Finding this “essence” is what sparklines is all about.