What makes a good design principle?

  1. Good design principles are memorable.
  2. Good design principles help you say no.
  3. Good design principles aren't truisms.
  4. Good design principles are applicable.

Of these, probably the most important is #3. Ström and others encourage applying the reversibility test: a principle passes the test if the opposite of that principle is something a reasonable person might believe. A principle like "make users happy" fails this test because no organization would adopt the opposite, "make users unhappy" – therefore the principle is useless for making design decisions.