Kenji's Ticket-Tier Divergence — Schema
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Flat CSV in kenji-ticket-tiers.csv. One row per month.

Columns
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Column                       Type     Description
---------------------------  -------  -------------------------------------------------------------------------
month                        text     Three-letter month code in fiscal-year order (Jul, Aug, ..., Jun).
tier2_tickets                integer  Count of tier-2 tickets resolved in the month.
tier2_mean_resolution_hours  decimal  Mean resolution time for tier-2 tickets in hours, to one decimal.
window                       text     Either pre_automation (Jul–Mar) or post_automation (Apr–Jun).

Row inventory
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- 12 rows — one per month.

Total: 12 rows.

Deliberate design choices
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The dataset carries both metrics on every row so the reader can reproduce either Kenji’s original stacked-area chart (which used tier-2 tickets alongside tier-1, tier-3, and escalations on one canvas) or the small-multiples rebuild (which uses tier-2 volume and resolution time on two panels sharing the nine-month x-axis).

The window column is redundant with the month column (given the automation-month convention) but explicit tagging makes the two windows testable in a single group-by without repeating the automation-month rule in downstream code.

Resolution time is stored to one decimal to match the graduated climb Chapter 4 walks through (each month adds ~0.1 hours until the automation window, where the increment jumps to ~0.2/month).

License
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Released for teaching use alongside The Defensible Decision. Use freely.