How to Present Data in Figures and Tables DEAN P. CURRIER, Ph.D.
headers of scientific publications Re frequently do not read each article in its entirety, but readers often look at the figures and tables which, if presented well, may entice the reader to read the article. Figures and ta bles are appealing and informative visual presentations of research results or text material. Because authors wish to reach as many readers as possible, authors must be familiar with the general principles of constructing figures and tables. My purpose is to provide authors, or potential authors, with information which may be of assistance in the visual presentation of their results.
Figures are used to provide an overview of the results of the study or presentation and should observe simplicity. Detailed information or results are not to be placed in figures. Figures may be drawings or photographs to illustrate text material or graphs which show comparisons or trends.
instance, in the "Suggestions From the Field" section of the Journal, readers might have difficulty understanding what the author is trying to present unless a picture accompanies the text. The picture should be clear and as uncluttered as possible. The item should be photographed against a plain background and should be in the forefront of the picture. In submitting photographs to the Journal, authors must remember that photographs will usually be reduced to fit in one column or part of one column. If the photograph is cluttered with excessive material, the important point which the author wishes to illustrate will be lost completely in the reduction. Photographs ac companying articles should be black and white glossy prints. Instantly produced pictures usu ally do not have as good a contrast as black and white prints. Often, line drawings are more effective than a photograph. A line drawing effectively omits everything which is not essential to the under standing of the points which the author is trying to make.
Drawings and Photographs
Graphs
A drawing or photograph serves to clarify text material so that the reader sees clearly the subject which the author is presenting. For
Graphs, like photographs, provide instant communication to the reader. By looking at a graph the reader can readily observe the trends or comparisons which, if presented in the text, might be obscure. Graphs should be fully self-explanatory and should not require num bers within the body of the graph. A key,
FIGURES
Dr. Currier is Assistant Professor, Department of Physical Therapy, Medical College of Georgia, Au gusta, GA 30904.
768
PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
Let's Reduce The Communication Gap
90 —
RESPONSES O F GRADUATES
80 —
60 —
50 — 40 — 30 —
111
20 —
10 —
ABOVE AVERAGE VERAGE
AVERAGE
BELOW AVERAGE
Fig. 1. A simple bar graph. Note spacing between bars and key in the graph. (From Conine TA: A survey of the graduates of a professional physical therapy program. Phys Ther 52:855-861, 1972.)
however, which identifies the different effects or methods may be placed within the body of the graph (Fig. 1). The author is responsible for the impression which a graph conveys; therefore, he must present the graph in a manner which will not deceive the reader. The spacing of units or
COMMITTEE MEETING
STUDENT ADVISEMENT
ADMINISTRATION CONSULTATION
RESEARCH
WRITING
CLINICAL TEACHING
CLINICAL DUTIES
OTHER
0
10
20
30
40
50
60
PERCENTAGE
70
80
90
100
(N = 21 2)
Fig. 2. A bar graph with horizontal rather than vertical bars. (From Conine TA: Teacher preparation based on functions and opinions of educators. Phys Ther 53:876-884, 1973.) Volume 55 / Number 7, July 1975
divisions along the horizontal scale (abscissa) and vertical scale (ordinate) must be propor tioned similarly. Disproportioned spacing of units along one scale will overemphasize one variable or characteristic and thus deceive the reader. Bar graph. One of the simplest types of graphs for presenting discontinuous data is the bar graph which appears in Figures 1 and 2. The bar graph presents frequencies of things or events by a series of bars or rectangles placed horizontally or vertically with the length or height of the bars proportional to the amount or frequency of the things being measured. Usually each bar is separated by uniform spaces which are generally one-half the width of a bar and which enable the reader to make compari sons among data quickly and conveniently. Histogram. A histogram is similar in form to a bar graph; however, it presents continuous or grouped data and shows the frequency of things occurring within each group. The histogram is constructed by representing scores or observa tions which have been grouped on the abscissa, while representing the frequency of the scores or observations on the ordinate. The bars of histograms are adjacent to each other so that 769
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
RESPONSES O F EMPLOYERS
70 —
I40-,
120-
i 60-
5
6
7
Mi 11 i a m pt rtt Fig. 3. A histogram. Note that bars are adjacent to each other for ease in discerning the frequency of grouped data. (From Nelson R: Facial nerve excitability: Its reliability, objectivity, and descriptive validity. Phys Ther 5:387-390, 1971.)
the reader can readily discern the frequencies which the author is trying to show (Fig. 3). Broken-line graph. A broken-line graph is useful for comparing changes occurring in one characteristic with changes occurring simultane ously in another characteristic. The graph is constructed by plotting pairs of points of corresponding values of the two characteristics and joining the consecutive points by a series of straight lines. The independent variable is plotted on the abscissa and the dependent variable is plotted on the ordinate. The graph is adapted conveniently to show different effects and methods which affect the two variables (Fig. 4). Pie graph. The pie or circle graph is used most frequently to represent apportionment of a whole into its component parts. The compo-
Fig. 4. A broken-line graph showing how the changes in one variable influence changes in a second variable. (From Bishop B: Vibratory stimulation: Part I. Neurophysiology of motor responses evoked by vibratory stimulation. Phys Ther 54:1273-1282, 1974.) 770
Effect o f initial muscle length on TVR
Tension
4-
10 c
60 c 2 -
10
20
30
40
seconds PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
100-
STAND
' B Y T/ME
Fig. 5. A pie graph is used to show values of pans in relation to a whole. (From Gray JM: Function of nonprofessional physical therapy personnel. Phys Ther 44:103-109, 1964.)
nent parts can be expressed as percentages, probabilities, or fractions of a whole quantity. Labeling within the apportioned areas is permis sible in the pie graph in order to prevent cluttering (Fig. 5). TABLES
Tables provide for the orderly and detailed arrangement of data. Tables provide clarity and increased meaning to data which the narrative form of presentation often fails to accomplish. When data are presented in the tabular form of columns and rows according to logical and pertinent classifications of the subject matter, the reader can interpret the results of the article readily and conveniently. Tables should clarify or emphasize certain aspects of the text but should not repeat the Volume 55 / Number 7, July 1975
text. Often tables can present detailed material easily in less space than would otherwise be required in the text (Fig. 6). In constructing tables, authors should limit the table to as few points as possible. Complex tables will be passed over because they make tedious reading. In developing a table, authors should think of the size of a Journal page. A table is limited usually to one column in the article and must be limited to no more than two columns unless it is presented sideways in the text which, of course, makes it difficult to read. Only common abbreviations should be used in a table. The title of the table should indicate precisely what the table is about. Each column and row of numerical data or variables must be labeled clearly with an identifiable unit. The same number of decimal places should be used when reporting data of the same 771
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
"•65%
TABLE 2
Summary of Analysis of Variance for Muscle Tension during Test and Retest Source
A (Elbow Angles)
AS
Total a
SS
MS
40
Test Retest
14653.51 17820.20
366.34 445.51
2
Test Retest
3629.89 5539.19
1814.94 2769.59
80
Test Retest
3023.51 3638.34
37.79 45.48
122
Test Retest
21306.91 26997.73
F
48.02 3 60.90 a
Significant at .01 level.
Fig. 6. A table can be used to present statistical data with greater clarity than can be done in the text. (From Currier DP: Maximal isometric tension of the elbow extensors at varied positions. Part 1. Assessment by cable tensiometer. Phys Ther 52:1043-1049, 1972.)
characteristic. Zeros should be used in a table to indicate "none" if the rest of the data is numerical. If data are not available, a series of dots (. . .) should appear in the appropriate column. ,
SUMMARY AND CONCLUSIONS Good figures and tables can enhance a written presentation by offering variety and
772
convenience to the reader. Remember, figures present an overview and are kept simple and uncluttered; tables are reserved for presenting detail. Although the most commonly used figures and table have been presented, the variations of ways in which data can be displayed is really dependent upon the imagina tion of the author. The author presenting pictorial information, however, must follow the general rules and guidelines.
PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
Subjects
DF
headers of scientific publications Re frequently do not read each article in its entirety, but readers often look at the figures and tables which, if presented well, may entice the reader to read the article. Figures and ta bles are appealing and informative visual presentations of research results or text material. Because authors wish to reach as many readers as possible, authors must be familiar with the general principles of constructing figures and tables. My purpose is to provide authors, or potential authors, with information which may be of assistance in the visual presentation of their results.
Figures are used to provide an overview of the results of the study or presentation and should observe simplicity. Detailed information or results are not to be placed in figures. Figures may be drawings or photographs to illustrate text material or graphs which show comparisons or trends.
instance, in the "Suggestions From the Field" section of the Journal, readers might have difficulty understanding what the author is trying to present unless a picture accompanies the text. The picture should be clear and as uncluttered as possible. The item should be photographed against a plain background and should be in the forefront of the picture. In submitting photographs to the Journal, authors must remember that photographs will usually be reduced to fit in one column or part of one column. If the photograph is cluttered with excessive material, the important point which the author wishes to illustrate will be lost completely in the reduction. Photographs ac companying articles should be black and white glossy prints. Instantly produced pictures usu ally do not have as good a contrast as black and white prints. Often, line drawings are more effective than a photograph. A line drawing effectively omits everything which is not essential to the under standing of the points which the author is trying to make.
Drawings and Photographs
Graphs
A drawing or photograph serves to clarify text material so that the reader sees clearly the subject which the author is presenting. For
Graphs, like photographs, provide instant communication to the reader. By looking at a graph the reader can readily observe the trends or comparisons which, if presented in the text, might be obscure. Graphs should be fully self-explanatory and should not require num bers within the body of the graph. A key,
FIGURES
Dr. Currier is Assistant Professor, Department of Physical Therapy, Medical College of Georgia, Au gusta, GA 30904.
768
PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
Let's Reduce The Communication Gap
90 —
RESPONSES O F GRADUATES
80 —
60 —
50 — 40 — 30 —
111
20 —
10 —
ABOVE AVERAGE VERAGE
AVERAGE
BELOW AVERAGE
Fig. 1. A simple bar graph. Note spacing between bars and key in the graph. (From Conine TA: A survey of the graduates of a professional physical therapy program. Phys Ther 52:855-861, 1972.)
however, which identifies the different effects or methods may be placed within the body of the graph (Fig. 1). The author is responsible for the impression which a graph conveys; therefore, he must present the graph in a manner which will not deceive the reader. The spacing of units or
COMMITTEE MEETING
STUDENT ADVISEMENT
ADMINISTRATION CONSULTATION
RESEARCH
WRITING
CLINICAL TEACHING
CLINICAL DUTIES
OTHER
0
10
20
30
40
50
60
PERCENTAGE
70
80
90
100
(N = 21 2)
Fig. 2. A bar graph with horizontal rather than vertical bars. (From Conine TA: Teacher preparation based on functions and opinions of educators. Phys Ther 53:876-884, 1973.) Volume 55 / Number 7, July 1975
divisions along the horizontal scale (abscissa) and vertical scale (ordinate) must be propor tioned similarly. Disproportioned spacing of units along one scale will overemphasize one variable or characteristic and thus deceive the reader. Bar graph. One of the simplest types of graphs for presenting discontinuous data is the bar graph which appears in Figures 1 and 2. The bar graph presents frequencies of things or events by a series of bars or rectangles placed horizontally or vertically with the length or height of the bars proportional to the amount or frequency of the things being measured. Usually each bar is separated by uniform spaces which are generally one-half the width of a bar and which enable the reader to make compari sons among data quickly and conveniently. Histogram. A histogram is similar in form to a bar graph; however, it presents continuous or grouped data and shows the frequency of things occurring within each group. The histogram is constructed by representing scores or observa tions which have been grouped on the abscissa, while representing the frequency of the scores or observations on the ordinate. The bars of histograms are adjacent to each other so that 769
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
RESPONSES O F EMPLOYERS
70 —
I40-,
120-
i 60-
5
6
7
Mi 11 i a m pt rtt Fig. 3. A histogram. Note that bars are adjacent to each other for ease in discerning the frequency of grouped data. (From Nelson R: Facial nerve excitability: Its reliability, objectivity, and descriptive validity. Phys Ther 5:387-390, 1971.)
the reader can readily discern the frequencies which the author is trying to show (Fig. 3). Broken-line graph. A broken-line graph is useful for comparing changes occurring in one characteristic with changes occurring simultane ously in another characteristic. The graph is constructed by plotting pairs of points of corresponding values of the two characteristics and joining the consecutive points by a series of straight lines. The independent variable is plotted on the abscissa and the dependent variable is plotted on the ordinate. The graph is adapted conveniently to show different effects and methods which affect the two variables (Fig. 4). Pie graph. The pie or circle graph is used most frequently to represent apportionment of a whole into its component parts. The compo-
Fig. 4. A broken-line graph showing how the changes in one variable influence changes in a second variable. (From Bishop B: Vibratory stimulation: Part I. Neurophysiology of motor responses evoked by vibratory stimulation. Phys Ther 54:1273-1282, 1974.) 770
Effect o f initial muscle length on TVR
Tension
4-
10 c
60 c 2 -
10
20
30
40
seconds PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
100-
STAND
' B Y T/ME
Fig. 5. A pie graph is used to show values of pans in relation to a whole. (From Gray JM: Function of nonprofessional physical therapy personnel. Phys Ther 44:103-109, 1964.)
nent parts can be expressed as percentages, probabilities, or fractions of a whole quantity. Labeling within the apportioned areas is permis sible in the pie graph in order to prevent cluttering (Fig. 5). TABLES
Tables provide for the orderly and detailed arrangement of data. Tables provide clarity and increased meaning to data which the narrative form of presentation often fails to accomplish. When data are presented in the tabular form of columns and rows according to logical and pertinent classifications of the subject matter, the reader can interpret the results of the article readily and conveniently. Tables should clarify or emphasize certain aspects of the text but should not repeat the Volume 55 / Number 7, July 1975
text. Often tables can present detailed material easily in less space than would otherwise be required in the text (Fig. 6). In constructing tables, authors should limit the table to as few points as possible. Complex tables will be passed over because they make tedious reading. In developing a table, authors should think of the size of a Journal page. A table is limited usually to one column in the article and must be limited to no more than two columns unless it is presented sideways in the text which, of course, makes it difficult to read. Only common abbreviations should be used in a table. The title of the table should indicate precisely what the table is about. Each column and row of numerical data or variables must be labeled clearly with an identifiable unit. The same number of decimal places should be used when reporting data of the same 771
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
"•65%
TABLE 2
Summary of Analysis of Variance for Muscle Tension during Test and Retest Source
A (Elbow Angles)
AS
Total a
SS
MS
40
Test Retest
14653.51 17820.20
366.34 445.51
2
Test Retest
3629.89 5539.19
1814.94 2769.59
80
Test Retest
3023.51 3638.34
37.79 45.48
122
Test Retest
21306.91 26997.73
F
48.02 3 60.90 a
Significant at .01 level.
Fig. 6. A table can be used to present statistical data with greater clarity than can be done in the text. (From Currier DP: Maximal isometric tension of the elbow extensors at varied positions. Part 1. Assessment by cable tensiometer. Phys Ther 52:1043-1049, 1972.)
characteristic. Zeros should be used in a table to indicate "none" if the rest of the data is numerical. If data are not available, a series of dots (. . .) should appear in the appropriate column. ,
SUMMARY AND CONCLUSIONS Good figures and tables can enhance a written presentation by offering variety and
772
convenience to the reader. Remember, figures present an overview and are kept simple and uncluttered; tables are reserved for presenting detail. Although the most commonly used figures and table have been presented, the variations of ways in which data can be displayed is really dependent upon the imagina tion of the author. The author presenting pictorial information, however, must follow the general rules and guidelines.
PHYSICAL THERAPY
Downloaded from https://academic.oup.com/ptj/article-abstract/55/7/768/4567684 by Washington University in St. Louis user on 12 February 2019
Subjects
DF
