Four Pieces, One Footnote
You are coding parcels at a plant annex. The scheme sheet gives four bins:
- Bin A: ZIP 300–349
- Bin B: ZIP 350–399
- Bin C: any piece endorsed "HOLD," any ZIP
- Bin D: any oversized or irregular piece, any ZIP
A footnote gives precedence: oversize/irregular outranks HOLD, and HOLD outranks ZIP.
The next four pieces are:
- A flat, ZIP 372, no endorsement
- A parcel, ZIP 331, endorsed HOLD
- A tube, ZIP 358, endorsed HOLD
- A letter, ZIP 405, no endorsement
1. Assign each of the four pieces to a bin and show the rule you applied.
Read the worked answer
Work the footnote before the ZIP range every time; the ZIP range is the fallback, not the starting point.
- Bin B. Flat, no endorsement, no irregular shape → ZIP rule only. 372 falls in 350–399.
- Bin C. Parcel, ZIP 331 would be Bin A - but HOLD outranks ZIP, and nothing about the piece is irregular. HOLD alone controls.
- Bin D. Tube, ZIP 358, HOLD. This is the one that punishes ZIP-first thinking twice: ZIP says B, HOLD says C, but a tube is irregular, and irregular outranks HOLD. D wins.
- No bin. ZIP 405 is outside every range given. It is not Bin B by proximity.
The general rule: the more specific the condition, the higher it sits in precedence. Shape and endorsement are properties of the individual piece; ZIP is a property of a region and therefore the broadest, lowest-precedence test.
2. What do you do with piece 4?
Read the worked answer
Do not force it into the nearest bin. A piece coded by proximity is a piece that will be misrouted and then take a second pass to recover.
- Set it aside in a clearly marked out-of-range tray rather than on the belt or in an existing bin.
- Check the reverse of the scheme sheet for an out-of-range or "all other" instruction before escalating - scheme sheets usually have one, and a footnote that defines precedence suggests a fuller document.
- If there is no instruction, ask the supervisor or the scheme clerk and record the answer.
- Do not re-route it by guesswork even under time pressure; the cost of a misroute exceeds the cost of a two-minute question.
A single ZIP outside the published ranges is a signal that the scheme sheet is incomplete or that the piece is mislabeled - either way it is information, not an inconvenience.
3. Describe a self-check that would catch precedence errors like piece 3.
Read the worked answer
Precedence errors happen on the minority of pieces with more than one applicable rule. So the check should be proportional to that.
- Triage at a glance: split pieces into "plain" (one rule applies) and "flagged" (has an endorsement, is oddly shaped, or is oversized). Plain pieces get the fast ZIP pass.
- Flagged pieces get a deliberate second look against the footnote, in precedence order - shape first, then endorsement, then ZIP - said silently or aloud.
- Every flagged piece, 100% check. They are a small share of volume, so full checking is cheap and the error rate there is where the risk lives.
- Periodically audit a sample of plain pieces to confirm the fast pass is not drifting.
The reasoning: uniform checking of everything is unsustainable at volume and degrades into no checking at all. Concentrating attention where two rules collide is what keeps the check alive across a full shift.