=== Report 1: Order-level delivery reliability: weak carriers vs rest, 2025 (written by Bea) ===
Engineer's note: Delivery days computed as calendar-date difference (delivered_at::date - placed_at::date), matching the DATEDIFF(day, ...) definition used in Priya's report. Two rows expected, one per carrier_group.
REPORT: Order-level delivery reliability: weak carriers vs rest, 2025
QUESTION: In the same order-level metric I've already reported to Priya (pct within 5 days), how much better would our overall delivery reliability be if the three weak carriers matched everyone else?
carrier_group      | orders_fully_delivered | avg_delivery_days | pct_within_5_days | share_of_orders_pct
-------------------+------------------------+-------------------+-------------------+--------------------
All other carriers |                  13696 |              3.44 |              93.4 |                66.7
Weak three         |                   6837 |              5.19 |              66.8 |                33.3
(2 rows)

=== Report 2: Order-level delivery reliability: Albion Parcel vs rest, baseline vs collapse, 2025 (written by Ines) ===
Engineer's note: Aggregated across all tenants/merchants (not merchant-specific); delivery_days computed as delivered_at minus placed_at in fractional days using the single qualifying shipment per order, per the same attribution rule as the weak-carriers-vs-rest report.
REPORT: Order-level delivery reliability: Albion Parcel vs rest, baseline vs collapse, 2025
QUESTION: How much of the November-December delivery slowdown is specifically attributable to Albion Parcel, versus everything else?
carrier_group      | period   | orders_fully_delivered | avg_delivery_days | pct_within_5_days | share_of_period_orders_pct
-------------------+----------+------------------------+-------------------+-------------------+---------------------------
Albion Parcel      | baseline |                   2052 |               3.4 |              92.3 |                       13.3
All other carriers | baseline |                  13409 |              3.97 |              78.9 |                       86.7
Albion Parcel      | collapse |                    512 |              9.82 |              31.3 |                       10.1
All other carriers | collapse |                   4560 |              3.85 |              80.0 |                       89.9
(4 rows)

=== Report 3: Order-level delivery reliability: Lowlands Express by destination lane, 2025 (written by Bea) ===
Engineer's note: Delivery days computed as delivered_at minus placed_at (no other timestamp was specified for "delivery"); destination country taken from orders.shipping_address_id -> addresses -> countries.name as requested. All three lane_group rows are returned as expected (3 rows total, no truncation).
REPORT: Order-level delivery reliability: Lowlands Express by destination lane, 2025
QUESTION: How much better would Lowlands Express's orders perform, and how much would that help overall, if we only used it on its strong home lanes (Netherlands, Belgium, France) and moved everything else off it?
lane_group                          | orders_fully_delivered | avg_delivery_days | pct_within_5_days | share_of_orders_pct
------------------------------------+------------------------+-------------------+-------------------+--------------------
Lowlands core (NL/BE/FR)            |                   1581 |              4.34 |              72.9 |                 7.7
Lowlands non-core (other countries) |                    864 |              5.96 |              34.1 |                 4.2
All other carriers                  |                  18088 |              3.92 |              82.0 |                88.1
(3 rows)