Definition
Systematic list
A planned list that records every valid possibility once, in a checkable order.
What it means
Keep one choice fixed while you change the other choices in order. Then move to the next fixed choice. The pattern gives you a way to check that nothing is missing or doubled.
Remember it
Fix one choice, vary the rest, then move on.
Example
A code uses one letter, A or B, followed by 1, 2, or 3. Fix A first: A1, A2, A3. Then fix B: B1, B2, B3. The six-code list is complete and has no repeats.
Watch for
A long list is not automatically systematic. You must be able to explain why every valid case appears and why none appears twice.
Common mix-up
Systematic does not mean numerical or alphabetical order; it means a dependable order that proves completeness.
Exact meaning
A systematic list records possibilities by following a repeatable order so every valid case is included once and no case is repeated.