understanding and presenting data

8/7/2019 Understanding and presenting data

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Understanding dataNumbers, tables, charts and textJen Beaumont&Andy Botterill


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Contents

Numbers: how to present them

effectively Tables: how to understand and present

tables

Charts: interpreting charts and whatmakes it difficult

Text: the main rules for describingnumbers


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Know your audience and aims before

you present data

Audience

Who is going to see the data or who was it intendedfor?

What are this audience going to need to help them?

Aims

What are you trying to convey?

What data do you need?

How much detail do you need to include?

What is the best way to sell your message?

Tables, charts or text or a combination


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Know what you are trying to get out of data

Who was it intended for?

What are you going to need to help youunderstand?

Aims

What are you trying to get out of it?

How much detail do you need?


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Useful numbers

Whatever way you want to present numbers

then the way you write and align them isimportant

This is true for any form of presentation

You should round numbers appropriately they are easier to read and compare

You should use commas to separate 1,000s


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12,573,981

The way you write a number so that it

can be read

12573981

Can you read this number?

Or is this better?


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Here it might be sensible to use13 million

and 112 million

12573981

111894397

12,573,981

111,894,397

What about two numbers?


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Tables

Extracting information from a table is likeextracting sunlight from a cucumber

(Farqhuar and Farqhuar, 1891)


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Tables: What should be presented

Clear information

Concise information

Correct information


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Source: Times7 January 2008


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A good table? . (or not)

203672968Total

406589Luxembourg

58491643United Kingdom

81538628Germany

5215732Denmark

58020376France

Total populationCountry

Population of part of Europe 1995


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A good table? possibly

203,672,968Total

406,589Luxembourg

58,491,643United Kingdom

81,538,628Germany

5,215,732Denmark

58,020,376France

Total populationCountry



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even better

40.081.5Germany

100.0203.7Total

0.20.4Luxembourg

2.65.2Denmark

28.558.0France

28.758.5United Kingdom

Per centof total

Total population

(Millions)Country



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So, from this example ..

Less digits, effective rounding

Easier to understand

Easier to remember More information

Better information Some value added


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Order matters

Here are data for the number of houses built in 2003,2004 and 2005

24,000 22,000 23,000

And the same three numbers as a column24,000

22,000

23,000

Without any additional information which year wouldyou think was which?


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Principles for assessing tables 1

Are the figures rounded effectively?

Do they compare numbers in columns not

rows?

Does the table read left to right and top to

bottom?

Are there totals to right and bottom oftable?


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Principles for assessing tables 2

Does time run down or from left to right?

Are the columns and rows in natural or

size order?

Does the layout guide the eye?

Could it be simpler?


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The writing isnt there to fill up the page!

Dont ignore the edges headers, footnotes

and endnotes are there for a reason All properly produced tables have a lot of

information apart from the number you are

seeking you do not always have to be anexpert in the subject to understand them

You should always look at the labels and in

attached notes first They will help you interpret the data clearly


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Metadata or how to find out what a number

means and how to use it correctly

Metadata is the technical word for 'data about

data'. It is the term used to describe the summary

information or characteristics of a set of data

and can often be found in on line data outputsby clicking on something like this .

If the data are National Statistics then some

the descriptive information must be there.

i


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Metadata: an example

Where to find

evidence of goodpractice

https://www.nomis

web.co.uk/Default.asp


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Charts

A picture is worth a thousands words unless it is a

bad chart


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What is a chart supposed to show?

It should have an aim: the samedata can be presented in differentways for different purposes

When drawing a chart, check if thechart meets the aim: if not, discard

it and start again


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Mode of travel to work

0

20

40

60

80

100

Cardiff Newport Wrexham Powys Counties

Percentage

Car

Bus

Train

Other

Aim: To show the

differences inmodes of travelto work within

counties


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Mode

Modes of travel to work

0

20

40

60

80

100

Car Bus Train Other

Percentage

sCardiff

Newport

Wrexham

Powys

Aim: To show thedifferences of

modes of travel towork

between counties


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Mode of travel to work

0

20

40

60

80

100

Cardiff Newport Wrexham Powys Counties

Car

Bus

Train

Other

Aim: To show the differencesin modes of travel towork within counties

Mode

Modes of travel to work

0

20

40

60

80

100

Car Bus Train Other

Percentage

Cardiff

Newport

Wrexham

Powys

Aim: To show the differencesof modes of travel to work

between counties


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Format in Graphs

population

1994 1995 1996 1997 1998 1999 2000

Graph A

The scales have beenmanipulated toproduce differentimpressions

Graph Bpopulation

1994 1995 1996 1997 1998 1999 2000

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

27,000

28,000

29,000

30,000

32,000

31,000


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population

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

1994 1995 1996 1997 1998 1999 2000

It is correct to include

0 in the scale

population

0

5

10

15

20

25

3035

1994 1995 1996 1997 1998 1999 2000

T

housands

It may also be

clearer to simplifythe y axis labels


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Poor examples of

charts


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Source:

AnnualReport ofWine

StandardsBoard2005-06

A really bad chart


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Source: CAPC

Enquiries: 020 7126 4610

Rail only

Rail with transfer to LUL or

DLR

LUL or DLR only

Bus

Car

Other1

0

200

400

600

800

1000

1200

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Numberofpeople(thousands

1. Includes coach/minibus, taxi, powered two wheeler and cycle

Chart 1.4.1 People entering central London in the morning peak

Another really bad chart


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Zone 1

Zone 2

Zone 3

Zone

4/5/6 Zone 1

Zone 2

Zone 3

Zone 4/5/6

0

5

10

15

20

25

30

35

Percentage

Fare zone

Fare zone

Source: GLBPS

Enquiries: 020 7126 4553

Chart 1.2.3 Spatial distribution of bus journey stages by fare zone (2005/06)

Start zone?

Order?

An even worse chart


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Chart 1.2.4 Spatial distribution of Underground journey stages by fare zone(2004/05)

Zone 1

Zone 2

Zone 3

Zone

4/5/6

Zone 1

Zone 2

Zone 3

Zone 4/5/6

0

5

10

15

20

25

30

35

Percentage

Fare zone

Fare zone

Source: UUS

Enquiries: 020 7918 4599

1. Zones A,B,C,D are included in Zone 6 in the data.

Start zone?

Order?

And another


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Taken from The Times


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Taken from The Times


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Public Agenda: The Times 15 November 2006


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Someonedefinedthis as theWorst piechart everproduced

Source:

How stuffworkswebsite


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1st

Qtr

2nd

Qtr

3rd

Qtr4thQtr

East

North

0

50

100

East

West

North

One to be avoided


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1st Qtr2nd Qtr

3rd Qtr4th Qtr

East

West

North

0

20

40

60

80

100

East

West

North

Another one to be avoided


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1

97

6

1

9

7

8

1

9

80

1

9

8

2

1

9

8

4

1

9

8

6

1

9

8

8

1

9

9

0

1

9

9

2

1

9

9

4

1

9

9

6

40

50

60

70

80

90

100

And one similar to this was published

Wales Index

GB Index


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2nd Qtr

13%

1st Qtr

13%

4th Qtr

13%

3rd Qtr

61%

One to avoid!


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1st Qtr

2nd Qtr3rd Qtr

4th Qtr

Questionable use: visual comparison only

Ipsos MORI:


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psos OEnd of Year Review 2006

Missing data? Order?

Ipsos MORI: Order?


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pEnd of Year Review 2006

O deGap?


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Figure 1: Percentage of interventions identified in each

category

1 -

Universally

applied

5 - Early

problems

6 - Severe

problems

2 - Pre-

school

3 - School-

aged

4 - Adults

and elderly

Vi ibl t i t l i t t ith


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Visible percentage is not always consistent withactual percentage

535 Early problems

1496 Severe problems(white)

19174 Adults and elderly

463 School- aged

12222 Pre-school

46431 Universallyapplied

Actual

percentagefrom data

Apparentpercentage of

visible areaCategory


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Principles for Charts

Use only two dimensions and no

explosions!

Label effectively and start at zero

Create statistically correct charts

Use gridlines on graphs and charts


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Text: assess by the following rules

Is it written for the right audience?

Is there unexplained technical language?

Are there acronyms without reference?

Does it use plain English?

Does it use the rules for the presentation ofnumbers?


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Some examples

Hospital waiting lists rose by 3,217 to106,938. hospital waiting lists rose by 3,000 (3 percent) to 107,000

196,476 new houses were built in 1998

compared with 239,172 ten years earlier

House building is declining. In 1988 some240,000 new houses were built: in 1998around 200,000 were built.

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