Fable
A small note finds the door; a large file explains the whole story
The city archive originally lent out its materials by the whole scroll. When a reader asked a narrow question, the copyist hauled out a thick entire volume. The answer was indeed in the volume, but the reader often had to leaf through for ages to find that one passage.
The curator found it too slow, so he changed to cutting the files into many small slips of paper. Each slip held only a short passage, and lookups became faster; as long as the question contained similar content, the small slips were easily picked out.
New troubles also appeared. The slips of paper readers received often lacked cause and effect. A slip said 'handle according to level-three approval' but did not say who level three was; it said 'exceptions follow the old rules' but did not carry where the old rules were.
Someone suggested cutting the slips of paper a little longer. With more length came more context, but the hits became coarser; many questions needed only a sentence or two, yet a large block of irrelevant content was pushed onto the desk.
Another person suggested adding a summary paragraph to every small note. The summaries became more and more like new case files, maintenance costs rose, and situations appeared where the summary and the original text were inconsistent.
A young librarian took a different approach. He still used small slips of paper to find the door numbers, because the slips were fine-grained enough; but behind each slip hung the large file, chapter and neighboring passages it belonged to.
When a reader asks a question, the system first uses the small notes to match the most relevant locations, then brings the corresponding large parent dossiers to the table. The small notes handle the hit, and the parent dossiers handle the explanation.
Later, approval processes, product manuals, and contract templates were all organized this way. Lookup no longer swung between "small and fragmented" and "large and blunt"; instead, the two granularities each did what they were good at. The curator finally wrote a sentence on the index cabinet: finding answers requires precision, giving answers requires completeness. Later, readers also trusted the librarians more: they would not explain complex rules with just one disconnected sentence, nor dump an entire irrelevant volume on the table. Small notes lead the way, large files bear witness. The librarians also checked whether parent files were too large. If a small note dragged out half a room of materials, readers would still get lost; the size of both parent and child must match the question.