The longer the better

Monday, August 30th, 2010

More is more in time series. The longer, the more we can see. And learn. For example: The States has never bought as many houses as in 2005. And since 1964 not as few as today.

US new home sales. - Source: Financial Times, 2010-08-23, page 20.
Source: Financial Times, 2010–08–23, page 20.

Less is less in time series. The shorter, the less we can see. And learn. For example: If shares are better than houses.

The Dax in the course of the day. - Source: FAZ, no. 198, 2010-08-27, page 24.The Dax in three months course. - Source: FAZ, no. 198, 2010-08-27, page 21.
Source: FAZ, no. 198, 2010–08–27, page 24 and 21.

Many is more in time series. The Dax series above and the one below were published in the same FAZ newspaper. I learn: At the stock exchange one often arrives at the same place.

The Dax is unsteady. - Source: FAZ, no. 198, 2010-08-27, page 21.
Source: FAZ, no. 198, 2010–08–27, page 21.

Many, different, long is the most in time series. Aha: People smoke less, but don’t pay less.

Sale of cigarettes in Germany, revenues and tax revenue. - Source: FAZ, no. 198, 2010-08-27, page 19.
Source: FAZ, no. 198, 2010–08–27, page 19.

Time: the longer the better, the more the better.

A rule without If-Then

Sunday, November 15th, 2009

6 reasons for vacation. 2 years. 2 parts of Germany. 24 values. Sounds easy. It’s not. A lot to think about in this chart.

Motives for vacation in Germany - Source: Welt am Sonntag (WAMS), No. 43, 200-10-25, p.24
Source: Welt am Sonntag (WAMS), No. 43, 2009–10–25, p.24
Motivations of Germans for vacation, East (”Ost”) vs. West Germany, from top: new impressions, experience, being on travel, to indulge in something, relaxation, reactivation of memories.

Closeness connects: The headline connects with all first bars. It becomes graphical itself. But shouldn’t. It’s for all four bars.

Time is horizontal: We had that before. Here, a decrease is a movement to the left. Hard to understand for the eye.

Man with a hat: Two men stand beside each other. The smaller one wears a hat. How small is that one? Values to the right of the bar: better not this time.

Colours group: In WAMS all values for 1991 and all values for 2008. Might be ok. Not ideal here.

Checkered is out: Stripes in the background are funny. And decrease readability.

Most important: reason, years, change between years, part of Germany and variance between East and West – all packed into the vertical. Too much.

Urlaubsmotive der Deutschen - Redesign als Grafische Tabelle
Source: DeltaMaster

My rule: Use two visual axes: vertical and horizontal, if it helps. Doesn’t always work. Here it’s ok.

Listen to the pattern II

Wednesday, April 15th, 2009

Johannes Kreidler gives time series a sound. I did that two years ago. In fact, I copied it from him*.

I guess Johannes wants to make fun of the crisis. Businesses take this very seriously. Your human ear is a lot faster than your eye. The eyes see what the ears have already heard. Such as a ranking with one high, some middle and a lot of small values. A very characteristic sound pattern. Possibly irritating. But that is good. You think about it.

This is the sound of some of the data from his video without fun:

Lehman Brothers

General Motors

Microsoft

My old sparklines with new data:

Click on the speaker symbol to hear the crisis.

* Source: Bissantz, Nicolas: Innovative Produkte: DeltaMiner. In: WIRTSCHAFTSINFORMATIK 43 (2001) 1, pp. 77–80.

Good luck is not enough to understand business charts

Monday, December 31st, 2007

Business charts are losers. Its only good luck if they work at all. He has shown some basic problems of them. With mine here, you need more brains than luck to find the truth.

Three time series

Each series increases with the same amount per month. The first increases by 5, the second by 25 and the third by 30. All increase with the same relative dynamic. From January to February by 50 %, next months by 33 %, then 25, 20, 17, 14, 13, 11, 10, 9, 8 %.

The eye is sure to see something different. The increase of the bottom most series seems dull compared to the top most. And even a difference in dynamics between the two top most series appears to be plausible.

All wrong.

Sparklines are much better suited. They present the first series as series 1 65, the second asseries 2 325 and the third as series 3 390. More general: Want to compare different time series? Then scale them individually. It doesn’t work in one single chart.

Small things that make a big difference

Wednesday, December 13th, 2006

Edward says: Use sparklines. Sparklines are data words. Or word graphics. A number without a history is boring. And can mislead. Even so, newspapers show lots of individual numbers. Deutsche Telekom’s revenues in the last quarter. The latest unemployment rate. Yesterday’s Dow Jones index. There’s room for a sparkline at the side. The size of a word. It shows nothing but the pattern of the values to date. You immediately understand it though. Whether it was higher some time in the past. Whether it’s been going up or down for a while. Whether it’s currently close to the historical high or low.

Here’s the development of the euro exchange rate compared to the US dollar. Since its introduction as book money on 1 January 1999 until today 1.32. Almost 3,000 values.

1. It’s not a sparkline without a number after it.

A sparkline is not simply a small time series. It needs the number after it. A sparkline doesn’t work without the number. If it’s there, we can see whether the previous numbers were totally different, slightly different, or more or less unchanged. We often don’t need to know things more precisely.

Wrong Right
Germany 37.7
France 130.4
Austria 75.1
Switzerland 56.6
Germany 37.7
France 130.4
Austria 75.1
Switzerland 56.6

You can add minimum or maximum to them if you wish. Or the initial value on the left.
You can’t write anything in the sparkline itself. Otherwise it will become larger than a word again.

2. The number belongs on the right.

The sparkline shows the number’s past. The number is the last point in the time series. That’s why the number belongs there. You should put things next to each other if they belong to each other. If a value’s on the left, you think it’s the first point in the journey through time. That’s why a sparkline’s number always belongs on the right.

The example shows how confusing it is if it’s done wrongly.

Wrong Right

Source: www.businessweek.com, retrieved 2006–12–12. Redesign: Me.

3. Scaling a sparkline impacts its meaning.

Careful! Scaling is important. Sparklines are small. Scaling is therefore very, very important. You often have several sparklines to compare. If you use the same scale for all of them, you are comparing the patterns and magnitudes of the series of values as well. That only works with similar values. If you use individual scales, you are merely comparing the patterns of the series of values. You compare the magnitudes using the numbers.

Scaled identically Scaled individually
South 9,786,026
North 2,812,324
East 743,415
West 140,476
South 9,786,026
North 2,812,324
East 743,415
West 140,476

Bars integrated in the table help you compare.

Scaled individually
South 9,786,026
North 2,812,324
East 743,415
West 140,476

4. Bars or lines?

Bars are easier to read. But they take up more space. I use bars for short time series, and lines for long ones. Mostly.

Short series Long series

5. Sparklines supplement figures, but do not replace them.

Sparklines are extremely nice in tables. Normally, tables show values for a point in time. Then you want to know how it was before then. So add sparklines. Sparklines can be used to incorporate the past of all values in nearly every table. But it’s wrong to omit the values altogether.

League table just with values

Wrong! Sparklines instead of values

Right! Sparklines and values

6. Sparklines like colors, but do not depend on them.

Publishers are still slightly afraid of sparklines. Especially of colored ones. Color printing is so expensive. But they don’t have to be in color. Sparklines work perfectly well without any coloring.

Single-colored

Now Min Max
Unemployment (1991–2009, in millions) 3.4 2.6 4.9

Multi-colored

Now Min Max
Unemployment (1991–2009, in millions) 3.4 2.6 4.9

SparkMaker helps you draw sparklines.