What one statement line actually is
A line looks like one thing and is four. The date, the type, the amount and the running balance are each a field, and the fourth is derivable from the other three - which is what makes a statement checkable rather than merely readable, and what makes a gap findable at all.
- fields
- 4
- derivable from
- any 3
- lines in a month
- 240
- reconciliation
- 15 minutes
A statement line carries four fields: the date, the type, the amount and the running balance after it. Any three derive the fourth, because the running balance is the previous balance plus or minus the amount. On the samples that is what makes a month of 240 lines checkable, and it is why the running-balance column matters more than the amount.
Four fields, one of them redundant
A statement that carries a running balance is self-checking: every line can be tested against the two balances either side of it. A statement that carries only dates and amounts is a list, and a list cannot tell a reader whether a line is missing.
The redundancy is the point. The amount tells the reader what moved; the running balance tells the reader what the movement did. When the two disagree with the balances around them, a line has been recorded twice, missed, or placed out of order, and the arithmetic says which.
| Field | Example | Derived from the other three by |
|---|---|---|
| the date | 27 Sep | nothing; it orders the statement rather than computing it |
| the type | bonus credit | nothing; it names the category rather than computing it |
| the amount | +20.00 | balance after minus balance before: 312.00 - 292.00 = 20.00 |
| the running balance | 312.00 | balance before plus the amount: 292.00 + 20.00 = 312.00 |
| four fields | - | any three produce the fourth |
What the line is not
A line is a record, not a balance and not a permission. It records that a movement happened, and the type records what kind of movement it was, but neither the amount nor the balance says whether the money can be withdrawn. That is a property of the category, and it is the subject of the next pages.
- Read the amount and the two balances either side of it, and check that they agree.
- Read the type, and decide which of the six categories the line belongs to.
- Read the date, and check that it sits in the order the balance suggests.
- Check whether the line is pending, which the two balances will not tell you.
- Repeat on the last line of the month first, where a disagreement usually sits.