Medical-data classification · 2026
From Policy Text to Traceable Classification
How can medical-data policy be converted into usable rules while keeping the supporting evidence attached?
Medical-data policies are written for human interpretation, but operational classification requires structured rules. The difficult part is not simply extracting a category name: a usable rule needs to retain the text that supports it, its place in the hierarchy, and its review state.
Prototype completed · substantive rule adjudication not performed
A real evidence trace
Medical personnel information: name, organization, and employee ID; original personal data; severe impact; General Data Level 3.
001医务人员信息 医务人员姓名,单位,工号 原始数据 个人 严重危害 一般数据3级Level 3
医务人员信息
proposed · Review required
Source linked
- 服务范围与对象
- 医务人员
- 医务人员信息
Deterministic projection
Provenance details
row_id: row_f62dbe167162
evidence_id: ev_226c9fd75fb7
chunk_id: doc_1_chunk_70
The problem
A plausible-looking hierarchy can still be unsupported. I therefore separated semantic extraction from structural construction.
The policy system uses a language model to extract classification records from source text and attach evidence references. Validation checks whether the extracted content remains grounded in the source. The hierarchy itself is then projected deterministically from accepted records rather than generated freely.
A separate metadata classifier starts from a rule catalog rather than allowing a model to invent labels. It retrieves candidate paths, applies deterministic context and domain hints, and uses constrained model selection only where needed. Once a path is selected, the classifier takes the security level stored in that rule instead of accepting a free-form level from the model.
Two systems, one interface
The two systems were originally connected only through their shared taxonomy. I later added a file-based conversion layer that carries compatible extracted rules into the classifier while preserving source references and upstream review state.
Policy-to-rule system
- Policy text
- Parsing and chunking
- Model-assisted classification-record extraction
- Evidence grounding and validation
- Deterministic hierarchy projection
Provenance-preserving file interface
- Extracted rule table
- Structural and provenance checks
- Classifier-compatible rule artifact
- Source references and upstream review state retained
Metadata classification system
- Metadata fields
- Deterministic candidate retrieval
- Context and domain hints
- Deterministic branch or constrained model selection
- Rule-level security lookup
- Review when uncertain or invalid
The conversion gate
The retrieval bottleneck
Top-20 candidate retrieval
Expected path appears within the first 20 retrieved candidates.
179/21981.74%
70 rows lost at the configured cutoff7 expected paths ranked 8–10 · 63 ranked 11–20
Seven-candidate LLM window
Expected path appears in the seven-candidate window exposed to the constrained LLM branch.
109/21949.77%
Loss occurs at the seven-candidate cutoff; deterministic branches can use the broader candidate list, so the window rate is not a whole-classifier accuracy ceiling.
An interface trace
- Metadata fieldZGJG_DM
可建卡履历信息 转归机构代码
- Selected classification path
主题资源 / 电子病历数据库 / 基础字典 / 医疗机构信息表
- Rule-level securityLevel 2
- Source rule → linked policy evidence
row_fc8a2ce6031e
When a hint takes the wrong branch
For CS_RQ, a patient-field hint pushed the classifier toward a patient-information category and Level 3. The repository-provided expected path was an application-system category with Level 2.
The example matters because the error came from decision scaffolding rather than an unconstrained model output. Domain hints can improve automation while also creating systematic override errors.
Patient information
Level 3
Application system
Level 2
Expected label: repository-provided and source-derived; not independently adjudicated ground truth.
Boundaries
- Candidate-retrieval metrics are not final classification accuracy.
- The file-based interface is a prototype, not a production service.
- Traceability does not establish rule accuracy, human approval, medical correctness, or performance outside the tested taxonomy.
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