Metaphor to Measurement · Building a Pain Tagger

~8 min · Updated Sep 2025

Introduction

Pain language is highly metaphorical. Patients talk about pain as if it were a weapon, a wild animal, or a fire consuming their body. These metaphors are vivid, but they are also messy: no two patients use exactly the same words. For researchers, clinicians, or developers, this creates a challenge: how do you take figurative, varied expressions and make them measurable?

This article shows how I moved from metaphorical descriptions in the Language of Endometriosis Project to a compact taxonomy, then to consistent annotations, and finally into a tiny prototype pain tagger. The goal was not to solve everything at once, but to prove that patient language can be captured, structured, and transformed into features that power tools like the Explain My Pain app.

From metaphor to taxonomy

The first step was to define a taxonomy that handles both literal and figurative pain language. As outlined in Data Taxonomy for Pain Language, the schema includes five core categories and a layer of metaphor entailments.

In the Endometriosis data, metaphor was not noise. Patients reached for metaphors because literal language felt inadequate. Capturing metaphors and their entailments made it possible to quantify what the patient was actually expressing.

From taxonomy to annotations

With the categories in place, I annotated the corpus using the lightweight QA strategies in Lightweight QA and Sampling Notes. Below are simplified examples to illustrate the mapping:

This transformed figurative descriptions into structured data points that could be counted, compared, and fed into a prototype.

From annotations to a prototype tagger

The first prototype was deliberately small and rule based. I used the annotated data to create feature lists and simple mappings:

When a new text was entered, the tagger scanned for these features and produced a structured pain profile:

Example input: “It is like fire ripping through my stomach at night.”

Why this matters

For annotators, this case study shows how careful tagging captures conceptual depth, not just surface words. For recruiters and project leads, it proves that a small, well managed annotation effort can power a working prototype. For developers, it offers a bridge from narrative descriptions to computational features that can be integrated into the Explain My Pain experience.

Closing

Building the pain tagger was a proof of concept: figurative pain descriptions can be transformed into structured data without losing their richness. The Endometriosis corpus provided the metaphors, the taxonomy gave the categories, QA kept things consistent, and the prototype demonstrated feasibility.

The last article in this series shares the small pieces that make this process repeatable: Annotation Snippets and Prompts I Reuse.