Visual Aids

for Oral Communication

Source: Denis Coulombier

Exchange of information

• Transform – data -> information -> knowledge

• Share– Paper (reports, articles)– Oral (presentations)

• Does our message come across?

Digital versus analog US pedestrians

Pedestrian crossingX = cross !

Digital pedestrian Analog pedestrian

BelgiumFrance

Burma Spain Zimbabwe

Analog pedestrians from around the world

Russia

Germany

US

Spain

France

Spain

Italy

"Rolling stones" from around the world

Distribution of signs by number of tumbling stones

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 42

Number of tumbling stones

012345678

Number of countries

Belgium

Germany

Chile

Ecuador

Argentina

Madeira

Distribution of signs by number of tumbling stones

http://www.ips.be/_wbm/rrot09.htm

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 42

Number of tumbling stones

012345678

Number of countries

Belgium

Germany

Chile

Ecuador

Argentina

Madeira

Digital or analog ?

Preparation of visual aids

• Text first, then visual aids

• The less fancy, the better

• Always related to what you say

Two types of visual aids

• Visual data– digital: tables– analog: graphs, charts, maps

• Visual reinforcement– bullet lists

Interacting with visual aids

• Visual data:

Give them the floor!

• Visual reinforcements: Leave them alone!

• Use the pointer appropriately• Do not forget the audience

Visual dataTables, charts, maps

• The simpler the better

• Digital or analog ?

• Walk the public through

Food Specific Attack Rates, Outbreak of Salmonellosis, Prison X, Dover, Delaware, September 1992

6.21.51.3 1.1

Food Specific Attack Rates, Outbreak of Salmonellosis, Prison X, Dover, Delaware, September 1992

Outbreak of Salmonellosis in a Prison, Delaware, 09/1992Food Specific Relative Risks, Saturday September 12, Lunch

¦

¦

¦

¦

¦

¦

¦

¦

Chicken Salad

Bread

Lettuce Leaves

Sliced Tomatoes

Pear Halves

Iced Tea

Margarine

Vegetable Soup

Food

0.5 5 50

Relative Risk (log scale)

Point estimate 95% CI

Graphical visual dataGraphs, charts and maps

• One point per slide

• No 3D

• Appropriate color palette

Characteristics of colors

Brightness HueQuantitative Qualitative

Palette for a quantitative variable

Gradient of grey

Light-dark palette

Palette for a qualitative classification variablesex, socioeconomic status, ...

Hue palette

Pattern palette

How to select a color or pattern

2 colors :

3 colors :or

AIDS Annual Rates per 100,000 Population for Cases Reported May 1990 through April 1991

Bad example for oral communication : mixture of analog and digital information + innapropriate color palette

Maine 4.6NH 4.6VT 3.6Mass 15.0Conn 14.9NJ 31.3Del 12.9MD 21.2DC 117.2

11.5

10.2

24.4

18.1

2.2 2.4

12.5

3.0

4.4

6.87.7

19.3

6.7

5.7

3.6

1.1

0.9 4.9

2.4

11.7

8.6

10.3

16.27.2 20.2

33.2

9.1

7.4

11.1

2.6

6.0 9.9

43.26.7

10.14.8

5.0

7.2

3.7

3.5

15.5

Legend (rate per 100,000)

0-5.9

6-11.9

12-19.9

20+

AIDS Annual Rates per 100,000 Population for Cases Reported May 1990 through April 1991

Better presentation for oral communication: analog display + quantitative light/dark palette

Rate per 100,000 population

0.0-5.9

6.0-11.9

12.0-19.9

>20.0

Visual reinforcements: bullet lists

• Use keywords

• < than 12 lines

• < 5 words per line

• Break line properly

MethodsThe karaoke slide

• We conducted a retrospective cohort survey including all people attending the visit of the park

• A case was defined as a papular or papulo-vesicular pruritic rash, among participants, 12 hours or more after the exposition to seawater

Methods

• Survey– retrospective cohort– all participants

• Case definition– rash (papular or papulo-vesicular)– > 12 hours after exposition

Effective text attributes

Sans serif font

Bold type

Lower case letters

Good contrast

Serif font

Normal type

UPPER CASE LETTERS

Poor contrast

Prefer Avoid

INEFFECTIVE TEXT ATTRIBUTES

• SERIF FONT

• THIN FONT

• UPPER CASE LETTERS

• POOR CONTRAST

Ineffective text attributes : the bar code font

Poor contrast

Small font