Presenting data professionallyBy Raymund B. HabaradasManagement and Organization DepartmentDe La Salle University

Florence Nightingale and the pie chartFlorence Nightingale is best remembered as the mother of modern nursing. Few realize, however, that she also occupies a place in history for her use of graphical methods to convey complex statistical information.

After witnessing deplorable sanitary conditions in the Crimea, she wrote Notes on Matters Affecting the Health, Efficiency and Hospital Administration of the British Army (1858), which included colourful polar-area diagrams where statistics being represented were proportional to the area of a wedge in a circular diagram. These charts visually illustrated that far more deaths were attributable to non-battle causes such as unsanitary conditions than to battle related causes.

Polar diagram, also known as the “Nightingale Rose Diagram”

Florence Nightingale and the pie chartWith this information, Nightingale helped to promote the idea that social phenomena could be objectively measured and subjected to mathematical analysis. And through this statistical approach, Nightingale convinced military authorities, Parliament and Queen Victoria to carry out her proposed hospital reforms – which resulted in a decline in the mortality rate for soldiers.

As Nightingale demonstrated, statistics provided an organized way of learning and led to improvements in medical and surgical practices. She also developed a Model Hospital Statistical Form that could be used to collect and generate consistent data and statistics. She became a Fellow of the Royal Statistical Society in 1858, an honorary member of the American Statistical Association in 1874, and has been acknowledged as a “prophetess” in the development of applied statistics.

Effective data presentationConverts raw data to a more

digestible form (e.g. summary tables, charts, and graphs)

Shows important information at a glance

Enhances understandingDelivers insight from dataPersuades decision makers

Table 1. I have a healthy daily diet

Response f %

Strongly agree 2 3.70%

Agree 25 46.30%

Neither agree nor disagree 18 33.33%

Disagree 9 16.67%

Strongly disagree 0 0.00%

Total 54 100%

To the statement “I have a healthy diet”, only half responded either with an “agree” (46%) or strongly agree (4%). About 33% neither agreed nor disagreed with the statement, while the other 17% disagreed. This translated into a mean score of 2.629.

Only half of Lasallians say they have a healthy diet.

Make it easy for your reader. Don’t make him work too hard, trying to understand your paper.

“If your paper is easy to read and understand, then much time and care must have been invested in writing it. That paper deserves a high grade.” – Sir Habs

Common mistakes in presenting tablesTitles are not descriptive enoughUnits of measure are not stated

clearlyColumn widths are inconsistent

and disproportionateTable sizes are inconsistentTables are not self-explanatoryNo notes to explain abbreviations

or unusual terminology

What’s wrong with this table?

Online spending and purchases by Internet users in selected countriesSpending Purchases

Belgium 790 6Denmark 1159 11France 509 8Germany 521 10Italy 454 7Netherlands 681 7Norway 1406 7Spain 452 5Sweden 1013 9United Kingdom 1201 18

What are the improvements?Table 1. Online spending and purchases by Internet users in selected countries in Western Europe, September 2006 (average)

CountrySpending (in Euro) Purchases

Norway 1406 7United Kingdom 1201 18Denmark 1159 11Sweden 1013 9Belgium 790 6Netherlands 681 7Germany 521 10France 509 8Italy 454 7Spain 452 5Source: Synovate and SPA Market Research - UK for the European Interactive

Advertising Association (EIAA), January 2007

Inconsistent table sizes

Table 1. I have a healthy daily diet

Response f %

Strongly agree 2 3.70%

Agree 25 46.30%

Neither agree nor disagree 18 33.33%

Disagree 9 16.67%

Strongly disagree 0 0.00%

Total 54 100%

Table 2. The canteens in school provide nutritious food

Response f %

Strongly agree 1 1.85%

Agree 21 38.89%

Neither agree nor disagree 23 42.59%

Disagree 8 14.81%

Strongly disagree 1 1.85%

Total 54 100%

Avoid distorting tables by indiscriminately pulling them vertically or horizontally, without regard for their original proportions. Be careful when you copy-paste and resize tables.

Consistent table sizes

Table 1. I have a healthy daily diet

Response f %

Strongly agree 2 3.70%

Agree 25 46.30%

Neither agree nor disagree 18 33.33%

Disagree 9 16.67%

Strongly disagree 0 0.00%

Total 54 100%

Table 2. The canteens in school provide nutritious food

Response f %

Strongly agree 1 1.85%

Agree 21 38.89%

Neither agree nor disagree 23 42.59%

Disagree 8 14.81%

Strongly disagree 1 1.85%

Total 54 100%

Make sure that tables are aligned across the manuscript. Column widths and heights, as well as the typefaces and font sizes, of similar tables must also be consistent. This makes for a professional-looking document.

Don’t forget to use the prescribed APA standards for tables – no vertical lines, and sparing use of horizontal lines.

Common mistakes in presenting diagrams or figures

Titles are not descriptive enoughDiagrams don’t have axis labelsAbsence of key or legendInappropriate diagrams or graphs

What is wrong with this graph?

More appropriate graph

For descriptive statisticsFrequency tablesCross-tabulationsMeasures of central tendency and

dispersionBar charts (single or multiple)HistogramsLine graphs (single or multiple)Pareto diagramsPie charts Box plotsPictograms

Frequency table and bar chart

Pareto diagram

Box plot components

Geograph

For inferential statisticsCross-tabulationsT-test resultsANOVA test resultsChi-square test resultsCorrelation test resultsRegression test results

ANOVA and correlationTable 9. ANOVA results – pre-final grade and final exams

Presenting data professionallyBy Raymund B. HabaradasManagement and Organization DepartmentDe La Salle University