ACID (atomicity, consistency, isolation, and durability) are a set of properties a database can support to guarantee data validity.
Applying this to note taking, an effective technique should produce notes that are:
Atomic. They contain only one idea.
Consistent. They always contain valid ideas.
Isolated. Their content can be modified without affecting other notes.
Durable. They are written to be permanent notes.
The ACID properties of a database.
The initial idea came from Andy Matuschak's atomic notes.