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The Detective’s Desk

MEDIUM · CASE FILE

A volume on the wrong shelf

Medium · MOSSBRIDGE REFERENCE LIBRARY

Four cataloguers each claim a proposed shelf for a book. The library uses a general year rule and one overriding exception. Also reconstruct the review register: it records who examined which source, independently of whether their later proposed answer is correct. Review slots describe order, not travel or clock times.

Investigate this case

Read the case file below, or open the interactive desk to examine records, keep notes and submit your reasoning. These are the case materials, without the solution.

Your assignment

Whose shelf assignment is wrong?

People and accounts

Suri West

Recorded account

“My book belongs on shelf B.”

Tavi Bell

Recorded account

“My book belongs on shelf C.”

Pera Lake

Recorded account

“My book belongs on shelf B.”

Rian Ash

Recorded account

“My book belongs on shelf A.”

Case records

Read each record on its own terms. A claim made by a person is different from a fact established by an independent record.

LINKED RECORD

Catalogue extracts

Pera’s book: atlas, 1968. Rian’s: ordinary, 1949. Suri’s: ordinary, 1950. Tavi’s: atlas, 1920.

This supplies each book’s type and year.

CONTEXT NOTE

Binding report

All four books have intact covers.

Binding condition is not part of the shelf rule.

PRIMARY RECORD

Shelf rule

Ordinary books published before 1950 go to shelf A; ordinary books from 1950 onward go to shelf B. Any atlas, regardless of year, goes to shelf C instead.

This provides the general rule and overriding atlas exception.

RECONSTRUCTION RECORD

Review register

This is the same investigation’s document review record. There are 3 ordered events, labelled Review 1, Review 2, Review 3. Each listed person, location and item occurs exactly once. These slots describe record order, not times from the analytical problem.

  • The event reviewed by Suri West occupies slot 2 (Review 2).
  • The event at Reading desk occurs immediately before the event reviewed by Tavi Bell (consecutive rows, with no event between them).
  • The event at Review bench occurs immediately before the event involving “Shelf rule” (consecutive rows, with no event between them).

Use each column’s choices exactly once. Verified relationships govern the board; proposed answers and later recollections do not override them.

RECONSTRUCTION RECORD

Review cross-check

The relationships below were verified independently. “A immediately before B” means A is in the row directly above B, with no row between them. Keep relationships from all worksheet sources together. The following later recollections are claims to test, NOT verified facts. Exactly one disagrees with the reconstructed board; this alone is not proof of deliberate deception.

  • The event at Review bench occupies slot 1 (Review 1).
  • The event involving “Catalogue extracts” occurs immediately before the event involving “Shelf rule” (consecutive rows, with no event between them).

Use each column’s choices exactly once. Verified relationships govern the board; proposed answers and later recollections do not override them.

Questions to resolve

When was the primary analytical record reviewed?

Use the interactive case desk to select your finding and cite the records that support it. The answer is checked there, and your progress stays in your browser.

Build your finding

Compare the records with each account. Work out what the evidence establishes, then separate that finding from anything it does not prove.

Open the interactive case More Medium case files