Conventions for graphs

General principles for graphs

Content

• Graphs should be standalone – that is, they should be able to be read and understood without having to read the surrounding text. For this reason, all abbreviations should be either written out in full in the figure or defined in a figure note below the figure, even if they have already been defined in the text.
• The usual convention is to place figure titles below the graph. This convention can also be used for web-based publications.
• Definitions of units, abbreviations and so on that are used in the graph are placed below the graph.
• The source of the information in the graph is placed below the graph after the definitions and notes.
• If the figure title is positioned below the graph, any abbreviations, explanatory notes or sources are placed between the bottom of the graph and the figure title (see example below).
• If the document is to be published online, alternative text should be attached to the figure so that it can be interpreted by assistive technologies (see Graph accessibility). 

Link to text

• Each graph should be referred to in the text as a figure (e.g. see Figure 3.1), and the graph should be placed as early as possible after its in-text mention.
• It is good practice to use the text to highlight key messages from the graph and then point to it with an in-text reference, rather than just announcing the figure.

Presentation

• Keep the graph as clean and uncluttered as possible. Any citations, caveats, logos, background shading, borders, and other nonrelevant data or graphic elements should be removed from within the figure.
• Common elements (e.g. appearance of legends, data elements, axes, typography, borders, colours, line styles) should be standardised across similar graphs in a document, to make the document more consistent and cohesive.
• Graphs should be copyedited and proofread so that they are consistent with the rest of the document.

Figure name or title

The following principles are recommended (see example below):

• Number figures consecutively within the document (e.g. Figure 1, Figure 2, Figure 3), or by section or chapter (e.g. Figure 2.1, Figure 2.2, Figure 4.1, Figure B5). Numbering by section is useful because changes in one section will not affect figure numbering in another section. This is especially important in long documents or those that have many figures.
• Place the figure title as its own paragraph below the graph, not within the graph.
• Use a title that describes the figure content, including where the data were collected and the period that the data cover, if appropriate:

• Use minimal capitalisation (only capitalise the first letter of the first word of the title and proper nouns).
• Use minimal punctuation to keep titles clean and uncluttered: follow figure numbers with a tab, not a colon, and do not place a full stop at the end. Using a tab also helps align the titles properly in an automatically generated contents list of figures:

• Spell out abbreviations in full in the title, wherever possible. Put any necessary detail in explanatory figure notes. The title should not cover more than 2 lines (preferably 1 line).
• For a series of graphs, give the same information in the same order.

Definitions, notes and sources

There are 4 main types of notes that may need to be used below a graph, illustrated in the example below:

• Definitions of acronyms used in the graph or figure name. The first line of figure notes should be any acronyms or abbreviations used in the graph, listed alphabetically. Only include abbreviations for units of measurement if they are unusual or if your audience might not be familiar with them (e.g. km does not need to be defined; µg may need to be defined, depending on your audience). Use a spaced =, and a semicolon to separate multiple entries. There is no need for a full stop at the end:

• Explanation of something in the graph or the figure name. The second line of figure notes is explanations. These are indicated in the graph by superscript letters (a, b, etc). Under the figure, list the letters (not superscripted), use a tab to separate the letter and note text, and start each note with a capital letter. Only insert a full stop at the end if the note is a full sentence or there is more than 1 sentence. Start each note on a new line:

• Other notes. The third line of figure notes is additional information about the whole graph, given as a general note. Use the word Note:, followed by a tab. Start the note with a capital and end with a full stop (notes should be full sentences). For more than 1 note, use a numbered list with a tab to separate the number and note text, starting on the line underneath the word Notes:

• Sources of information. The last line of figure notes is the source(s) of information. To refer to the source of specific data within the figure, use a superscript letter and a note, as described above. For the source of the whole graph, use the word Source: and insert the citation. If the document uses author–date (Harvard) style citations, this will be the author name and date, with parentheses around the date:

If the document uses numbered (Vancouver) citations, insert just the author name and a superscript reference number; do not include the date of the reference:

Do not put a full stop at the end of the source. If multiple sources have been used for the graph, use Sources: and a comma between entries. List sources chronologically, not alphabetically:

All references in figure notes should be cited in full in the reference list at the end of the document (see References). If the graph is completely original and there is no need to include a source, leave out the source.