Most charts consists of 2 - 4 "boxes" with some text inside them. Text in boxes is different from text in sentences and/or paragraphs. When writing an article, you don't have to worry about how long a line is, and/or whether it fits exactly in a certain amount of space.
Some guidelines about writing text in boxes:
- Make sure the point in each of the boxes has more or less equal weight in terms of content. You don't want box 1 to cover the entire presentation message, and box 2 to be a footnote detail.
- Think of text on slides as headlines. Strip out all unnecessary filler words (i.e., make it as short as possible), but add enough words to keep it specific (i.e., no generic buzzwords).
- Make sure that each box has roughly the same amount of text, covers the same number of lines. Yes, that means being a bit more verbose if one box is particularly short.
- Adjust line breaks to avoid orphan words on the next line, or line breaks that cut the words of a key concept in two (cognitive [break] dissonance).
When "writing" a chart: the content should be clear but the text should be balanced as well.
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