The Research Subway Map

What this module teaches: how to stay on one chain of questions to its end, what to do when a source answers a question from a different chain, and why breaking that discipline is where cognitive overload comes from. The mental model is a subway map: each chain is a colored line, each question–answer pair a station. This map adds two things chains really do: lines that share track — two chains riding the same rails until the moment they genuinely diverge — and a final intersection chart that fills in as you ride, showing how just three cases answer nine questions across three lines.

How to use this: ride the map station by station using the panel on the right — the train moves as you answer. The Notice and Duty Lines depart coupled, sharing track through the first two stations; when they split you’ll ride each to its terminus. At the corridor you’ll face a real choice; either answer teaches. And keep one eye on the chart below the map: every answer fills a cell, and by the end the columns tell their own story.

Demonstration — fictional cases & jurisdiction

Before boarding

Your client tripped over a tree stump left in the shared courtyard path of her apartment complex. To hold the landlord liable, three chains of questions have formed — but look at the map: two of them leave the first station on the same rails.

Duty Line — what must a landlord do about shared spaces, exactly?
Notice Line — must the landlord have known about the stump? (It can’t leave the station until a duty exists — so it rides the Duty Line’s rails at first.)
Standard Line — what makes a condition “unsafe” at all?

The intersection chart

The map, kept as a researcher would keep it: stations down the side, sources across the top. Cells fill as you ride — each dot takes the color of the line its station belongs to, so a case that crosses lines shows a column of mixed colors.

Station · question	Whitaker v. Sable Court	Pruett v. Alder Gate	Beale v. Juniper Row
E Elements of the claim
D Duty over shared spaces?
D1 Outdoor walks count?
D2 Duty to inspect?
N1 Knowledge required?
N2 Constructive notice standard
N3 Proving notice
U1 What is “unsafe”?
U2 Foresight, and proof

The subway rules

What you just practiced, as rules you can carry.

Rule 1Ride your line to the endA thread is closed when its last question is answered — not when a shinier question appears.

Rule 2Interchanges are gifts — if you log themA source that answers another line’s question costs ten seconds to note and saves you a station later.

Rule 3Never chase mid-lineExiting early leaves open questions behind you and opens new ones ahead — that pile of half-ridden lines is what cognitive overload is.

Rule 4Teleport only at a terminusWhen a line closes, jump to the next line’s first station and ride it fully — even where it crosses old track.

Rule 5The log is your transfer ticketThe Notes field is external memory. What’s written down doesn’t have to be held in your head.

Rule 6One case, many cellsSources refuse to stay in lanes — on this map three cases answered nine stations across three lines. The chart’s columns show every crossing, including the ones no corridor marked.