Using abbreviations in presentations
Generally, abbreviating words in presentations is not a great practice. Abbreviations can lead to ambiguity, which is never a good thing. When a message is developed to deliver specific information in the correct tone, abbreviations tend to undo some of the precision. For example, "incr." is frequently used; but sometimes it is difficult to know if it means "increase" or "incremental," even within context. Carefully written presentations avoid any type of ambiguity like this.
One abbreviation that is frequently seen is "n/a." This term has two meanings: not applicable and not available; but an explanation of which it means is rarely included on the slide. Using an abbreviation like this would be better if it is first referenced or footnoted about meaning.
Abbreviations can also take the form of symbols: the ampersand (&) and hash mark (#). Only use the ampersand when it is part of a company name, not in the place of "and." Instead of using the hash mark, use "no." instead. "No." is still an abbreviation, but it is more proper than "#."
Abbreviations are often used to economize on space. Instead of riddling a presentation with abbreviations to reduce the size of the text fields, try adjusting the line spacing or adjusting the dimensions and positioning of the text field. Often reducing the size of the font works well and does not impair readability.