If the burden of creating a diagram is too high (for a person), it is acceptable to write down (in short sentences) in itemization what you know before learning and as much as you remember after learning. However, in the author's experience, a map is better than a bullet list, because you can pull out better (more) memories by twisting your mind and thinking, "What was the connection to this? Also, even when writing things down, the quality of the memory will be higher if the items are related to each other rather than all lined up in parallel in a bulleted list.
Connecting related "concept labels" with each other
... While we are connecting lines and thinking about relationships, we often come up with things that are missing. This is why I believe that a concept map can salvage memory more deeply and pull more out than just bullet points.
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