Tables & Graphs

Franco ValdésConstanza Martínez

IMPROVING THE CLARITY OF TABLES

1.- How they are constructed 2.- How they are presented.

How they are constructed

Clarity of tables can be improved by paying attention to:

Size, complexity and organisation Captions and the prose descriptions of the tables

Large tables and figures are comparatively rare in most research articles Appendix

Rules

1. Split large tables into smaller ones2. Produce one overall summary table rather

than several small tables3. Provide clear captions that say what the table

is about, or tell the reader what the table shows (some people look at the tables first before reading the text)

Rules4. round off the numbers so that readers can make

meaningful comparisons more easily (giving data to four or five decimal points gives a misleading measure of accuracy)

Rules

5. Consider including averages (averages not only summarise the data but they also allow the reader to grasp better the spread of the scores presented)

6. Use the same layout for a series of tables to avoid subsequent confusion for the reader

Presenting tables

Common problems:

a) The positioning of the tables on the pageb) How tables are fitted into the space allocated

to themc) The space between the columns is

manipulated to make the table fit the space available, without taking into account whether or not that space is used to group the data appropriately

Prose descriptions of tables

Tables, and their contents, have to be explained to readers in the text

Prose descriptions of tables

‘Statistics-based’

Prose descriptions of tables

‘Reader-based’

Concepts you need to know: Variable: An element, feature, or factor that is

liable to vary or change. Frecuency: the frequency of a particular data value

is the number of times the data value occurs Axis: The vertical and horizontal lines that make

up the quadrants of a coordinate plane. The vertical axis is usally referred to as the y axis and the horizontal axis is usually referred to as the x axis.

Before starting…

Mainly problems of typesetting can affect the

appearance of graphs. And, like tables, graphs can be separated to make them fit in the space available, which can affect the perceived importance of the results.

The clarity of graphs

Pie charts, bar charts and line-graphs

Bar charts are easy to construct and are

usually clear, but, again, difficulties arise with the labelling if several different components on each measure are presented.

Bar charts

Line graphs are good for showing the

performance of two or more groups in different conditions, especially when the data from the different groups vary according to the condition they are in – technically, when there is an ‘interaction’ between them

Line graph

Tables and graphs provide different ways of

presenting data, each with their advantages and disadvantages.

Tables are probably best for displaying exact numbers; graphs for displaying trends in the data.

Trend: If the values of one set of data increases and the values of other set also increases then the two sets of related data shows a positive trend (outcome).

Notes

A pie chart is a circular chart divided into

sectors, illustrating relative magnitudes or frequencies. In a pie chart, the area of each sector is proportional to the quantity that represents. Together, the sectors create a full circle.

Pie charts are difficult to label and to read if they contain several segments.

Pie chart

Many of the features of tables and graphs discussed above are also relevant to their presentation in conferences. However, in conference presentations, it is best to present data drastically simplified.

Tables and graphs in conferences