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Data Visualisation- making your reports useful to business

Gary [email protected]

SQLBITS IIIHatfield - 13 September 08

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Introduction

Gary Crawford Customer Service Manager @ XLCubed

Sql Consultancy background Various projects & App Support for Oil Major

XLCubed since 2004 BonaVista


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Agenda

Objectives

Key tools of Data Presentation Tables

Best practice

Graphs ‘Classic’ graphs – best practice Pies & why they can be bad for you Graph Effects Finely beveled gauges

Dashboards The Halls of Shame & Fame Tips & techniques 5 minute example


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Tables

Use tables rather than charts where users will:• Look up precise, individual values• Compare individual values

So simple, what could go wrong?

“If the statistics are boring then you’ve got the wrong numbers” – Edward Tufte


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Tables – Gestalt Principles of Visual Perception

German School of Psychology, developed in 1930s


Principle of Proximity Principle of Continuity Principle of Closure

Principle of Similarity Principle of Connection Principle of Enclosure

Tables - Gestalt principle of Proximity Proximity

We perceive nearby objects as belonging to a group

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3 arrangements of 49 dots, 7 by 7 – 3 perspectives of what we are looking at

Tables – Gestalt principle of Continuity Continuity

When something is introduced as a series we tend to perpetuate it

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Even with inconsistent widths, the visual grouping still persists while the left or right alignment is in place


Tables – Gestalt principle of Closure Closure

Our minds don’t like open ends – they actively seek closure

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Even with the introduced space after 1st row we still perceive this as 7 columns


Tables – Hermann Grids

Optical illusion of seeing grey dots at the intersections of a black grid

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Headache inducing & to be avoided Gestalt tells us gridlines are unnecessary in most cases

Where they can’t be avoided, subdue the gridlines. They are at best supporting cast to the numbers.


Tables – recommendations Use white space and alignment to build the table

Right-Align columns of whole numbers, or whole numbers and text (i.e. headings)

Left align columns of text Just enough vertical white space in breaks to make them noticeable Relative spacing can affect the direction of reading

Avoid Gridlines - They tend to distract from the data If you think you can’t

- try alternate, light, fill colours Or just rules, i.e. one axis

If you really can’t, make them subtle - thin, and low saturation

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The Numbers Align at the decimal point Use thousand separators Precision - round in ‘000s if appropriate to clarify In most cases row & column totals help


Tables – applying the theory

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Visual Tables


Bringing chart components into tabular data

Same principles for layout

More later

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Graphs


“We now have easy access to creative programs which render all of us amateur graphic designers. Too often though the necessary knowledge about basic information design principles is missing.” - Rolf Hichert

“Simplicity is the ultimate sophistication” – Leonardo da Vinci

Use graphs rather than tables where:• Data sets are large and complex• The message is in the shape or distribution of the numbers• To reveal relationships among multiple values

A picture is worth a thousand words• Can be true of graphs, but too many times that’s not the

case

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Graphs – classic graphs


“Above all else show the data” – Edward Tufte

The purpose of a graph is to visualise the data The data components are the most important elements Everything else is ancillary, and should be muted in comparison

Less is more..

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Graphs – classic graphs


“Above all else show the data” – Edward Tufte

Plot area colour - is this helping? No, so remove it. Plot area borders & gridlines – remove / subdue Subdue the axes & Legend, Legend border Remove column borders

– difficult to see Product C Because of the abysmal colour scheme

Column & Bar Chart colours Shouldn’t clash horribly Low – mid saturation, they have a solid block, don’t overdo it

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Graphs – classic graphs & chart junk


“Maximise the data–ink ratio” – Edward Tufte

Removing the ‘Chart Junk’ leaves a simplified display, and a clearer message

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Graphs – colour in column & bar charts


Mid saturated colours for column & bar charts Similar intensity, unless one should stand out e.g. own brand

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Graphs – colour in column & bar charts


Don’t use Colour for colour’s sake Can be distracting & we’ll try to assign meaning

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Graphs –colour in line charts


Again, remove the chart junk Line Series Colours need to be stronger than for Columns & bars , less

body Make the lines fairly thick & easy to see, it’s the main aspect

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Graphs –graph sizing


Historically graphs & charts have been physically big Partly legacy issues of screen resolution etc

Is the smaller, inset chart more difficult to read than the larger? Free more screen real estate, & are often easier processed.

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Graphs –small multiples


Small Multiples Repetition of small charts, varying by one criteria If you understand one, you’ll understand them all

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Graphs – lies, damn lies & statistics


Columns & bars should be zero-based, or state very clearly they are not Are read by relative comparison of the length S East is actually 48% larger than S West, as opposed to 450% difference in

the data columns

Sales are flat Sales are soaring

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Graph Effects

PCs, graphics cards, displays & software march on ‘Tech Chart Junk

Lots of collateral imagery & effects now available on graphs Almost none of the peripherals helps in the central task of

displaying data Most common example – 3D

Compare the Q3 value for Spain in both charts

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Graph Effects – pimp my graph hall of.. 3D, transparency and reflection

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Graph Effects – pimp my graph hall of.. Our winner is

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Pie Charts – some issues & alternatives


Pie Charts are now fairly ubiquitous, Typically used for part – to whole relationships

Some issues Brain is working to convert 360 to a 10-base. Difficult to compare similar sized segments Don’t handle more than 4 or 5 values well Eye constantly moving to & from the legend

In many cases ranked bars will work better

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Ranked bars really only alternative for longer lists

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Multiple Pie Charts to show change particularly difficult to read

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Dashboards

"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)

Needs an audience and an objective

“By showing vast amounts of data within the eyespan, spatial adjacency assists comparison, search, pattern-finding, exploration, replication, review."

Edward Tufte, Beautiful Evidence (2006)


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Dashboards – some misconceptions

There is one dashboard which will serve everyone Not unless it’s a very small business Finance / Credit Control / Sales / HR / Ops

Mistaking Presentation for content Everyone wants some eye-candy reports right? No, typically people want reports which make their job easier If the content isn’t there it’s the Emperor’s New clothes If your dashboard shows 5 figures, you don’t need a dashboard, you need a

table or a sentence.

A Dashboard should literally look like a car / train / ship / plane dashboard No!


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Gauges & physical imagery – wow, that fast!


Gauges, thermometers, traffic lights & other physical imagery has proliferated most charting software

Running a business is not like driving a car / ship / boat Cars are real time, needing real time response Need to be able to glance at the instrumentation, not

analyse it in any depth Gauges highlight / exaggerate real time movement

Pressure build up in boiler #1! Business reports don’t move as you read them

You’ll need more than 4 gauges to ‘drive’ a business Guilty as charged (RIP)

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Gauges– Issues & Alternatives


Issues Space hungry, often displaying just 1 number 360 degree base, Imagery detracts from the data display Eye candy, largely non data-ink.

Alternatives A text number Simple Bars with a target line

‘Bullet Graph’ Invented by Stephen Few as a direct replacement for gauges

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Sparklines


Designed by Edward Tufte (Beautiful Evidence, 2006) ‘bare bones’ cut down chart, sized to fit within text or tables succinct, and located where they are discussed

"data-intense, design-simple, word-sized graphics“ Edward Tufte

No quantitative scale? Not intended for quantitative precision Purpose is to add context & perspective A quick view which can be quickly assimilated

Sparklines becoming mainstream business users see their value and actively seek them out

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Sparklines, Bullet Graphs & Visual Tables

Sparklines & Bullet Graphs can fit into, and significantly extend tabular data

Extension of ‘small multiples’

Typically used to show the most important numbers (current) but set their historical context


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Dashboards – Perception & Processing

Size All other things being equal we tend to focus on the

largest element first.

Colour and contrast after an element’s size the next thing that will

determine its prominence or visibility is its colour and how that contrasts with the overall colour

Use with caution “Avoiding catastrophe becomes the first principle in

bringing colour to information: Above all, do no harm." Edward Tufte


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Hall 1


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Hall 2


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Hall 2


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Hall 2


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ResourcesEdward Tufte

The Visual Display of Quantitative Information (1983)Visual Explanations (1990)Envisioning Information (1997)Beautiful Evidence (2006)

Stephen FewShow me the Numbers (2004)Information Dashboard Design (2006)

www.perceptualedge.com

William Cleveland Visualizing Data (1993)

Rolf Hichertwww.hichert.com

The Dashboard Spywww.dashboardspy.com

XLCubed blog www.xlcubed.com/en/blog.html


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