A Human-in/on-the-Loop Framework for Accessible Text Generation
Organizations: Universidad Carlos III de Madrid Av. Universidad, 30, Leganés, 28911, Spain
Abstract
Plain Language and Easy-to-Read formats in text simplification are essential for cognitive accessibility. Yet current automatic simplification and evaluation pipelines remain largely automated, metric-driven, and fail to reflect user comprehension or normative standards. This paper introduces a hybrid framework that explicitly integrates human participation into LLM-based accessible text generation. Human-in-the-Loop (HiTL) contributions guide adjustments during generation, while Human-on-the-Loop (HoTL) supervision ensures systematic post-generation review. Empirical evidence from user studies and annotated resources is operationalized into (i) checklists aligned with standards, (ii) Event-Condition-Action trigger rules for activating expert oversight, and (iii) accessibility Key Performance Indicators (KPIs). The framework shows how human-centered mechanisms can be encoded for evaluation and reused to provide structured feedback that improves model adaptation. By embedding the human role in both generation and supervision, it establishes a traceable, reproducible, and auditable process for creating and evaluating accessible texts. In doing so, it integrates explainability and ethical accountability as core design principles, contributing to more transparent and inclusive NLP systems.
Figures & tables
| Group | None | Some | All |
|---|---|---|---|
| Older adults | 16.6% | 58.9% | 24.5% |
| Participants with ID | 7.6% | 67.5% | 24.9% |
| Dimension | Operational check | Human-centered validation |
|---|---|---|
| Lexical clarity | Common words; explain acronyms | Comprehension tests |
| Syntactic simplicity | 20 words per sentence; one idea per sentence | Eye-tracking; reading times |
| Structural clarity | Logical order; headings; lists | Task success rates |
| Relevance | Preserve essentials; avoid redundancy | User judgments |
| Multimodal support | Glossaries; pictograms | Usability questionnaires; user testing |
| Prompt/model adaptation | Encode rules, glossary constraints, and domain specificity | HiTL prompt design; fine-tuning |
| Stage | Excerpt / signal | Framework interpretation |
|---|---|---|
| Original excerpt | “La caza y la pesca en la Comunidad de Madrid están sujetas a regulación especial y requieren una serie de trámites , entre ellos la obtención de licencia …” / “Hunting and fishing in the Community of Madrid are subject to special regulation and require a series of administrative procedures , including obtaining a licence …” | The source text contains a potentially difficult domain-specific term in an administrative context. |
| Initial adapted output | “…requieren una serie de papeleos …” / “…require a series of paperwork …” | The output simplifies the term, but may introduce an overly colloquial register and reduce administrative precision. |
| Detected issue/trigger | Readability may improve at the lexical level, but adequacy risk remains for domain register and terminology. / Possible mismatch between lexical simplicity and administrative appropriateness. | Trigger rule routes the case to HoTL review because lexical simplification alone does not guarantee appropriate wording. |
| HoTL-guided revision | Review the candidate substitute against the checklist dimensions for terminology, clarity, and domain adequacy. / Check whether the simplified term remains precise, understandable, and appropriate for the target context. | Checklist dimensions affected: lexical clarity, terminology consistency, and appropriateness of register. |
| Approved output | “…requieren varios trámites administrativos , entre ellos obtener una licencia …” / “…require several administrative procedures , including obtaining a license …” | Meaning-preserving simplification approved; the wording is clearer while maintaining administrative precision. |