This can apply to anything from lengthy quotations and long lists to detailed procedures and excessive raw data.
The second question to be answered when preparing to write an appendix is this one: Is it more helpful for the reader that this information be included in the main text or placed in a separate section?
These are: In fact, to successfully structure and write an appendix, the writer needs to have a clear understanding of the purpose of the writing in order to make decisions about which material should remain in the body of the work, and which material should be sent to the appendix.
When making decisions about writing an appendix and whether material should be placed in the appendix or incorporated in the main argument, the following question needs to be answered: Is this information or material essential to the central argument and topic?
The purpose behind writing an appendix is not to create a place for information that cannot be conveniently accommodated in the main text.
To write an appendix it is important to understand the two major perspectives that must be served in any successful piece of writing.
In such cases, this extra information is best relegated to the end of the text, by writing an appendix.
The type of information that is normally included when writing an appendix might be background or statistical information, graphical representations of research outcomes, detailed information pertaining to research or mathematical procedures, raw data, or any extra information that expands on a particular aspect of the topic in a tangentially relevant, rather than directly relevant way.
If it is, then it must be included in the main text.
If, however, it is too lengthy or too detailed it might be better to summarise it, including the essential points in the main text, and then writing an appendix to place the complete material in its own dedicated section.