Evaluating a Multi-Agent Voice-Enabled Smart Speaker for Care Homes: A Safety-Focused Framework
Organizations: University of Hull, UK · University of Southampton, UK · Connexin, Hull, UK · Leeds Teaching Hospital NHS Trust, UK
Abstract
Artificial intelligence (AI) is increasingly being explored in health and social care to reduce administrative workload and allow staff to spend more time on patient care. This paper evaluates a voice-enabled Care Home Smart Speaker designed to support everyday activities in residential care homes, including spoken access to resident records, reminders, and scheduling tasks. A safety-focused evaluation framework is presented that examines the system end-to-end, combining Whisper-based speech recognition with retrieval-augmented generation (RAG) approaches (hybrid, sparse, and dense). Using supervised care-home trials and controlled testing, we evaluated 330 spoken transcripts across 11 care categories, including 184 reminder-containing interactions. These evaluations focus on (i) correct identification of residents and care categories, (ii) reminder recognition and extraction, and (iii) end-to-end scheduling correctness under uncertainty (including safe deferral/clarification). Given the safety-critical nature of care homes, particular attention is also paid to reliability in noisy environments and across diverse accents, supported by confidence scoring, clarification prompts, and human-in-the-loop oversight. In the best-performing configuration (GPT-5.2), resident ID and care category matching reached 100% (95% CI: 98.86-100), while reminder recognition reached 89.09% (95% CI: 83.81-92.80) with zero missed reminders (100% recall) but some false positives. End-to-end scheduling via calendar integration achieved 84.65% exact reminder-count agreement (95% CI: 78.00-89.56), indicating remaining edge cases in converting informal spoken instructions into actionable events. The findings suggest that voice-enabled systems, when carefully evaluated and appropriately safeguarded, can support accurate documentation, effective task management, and trustworthy use of AI in care home settings.
Figures & tables
| Evaluation Component | Configuration / Scenario | Data Source | No. of Instances | Logged Outputs |
|---|---|---|---|---|
| Care-home trial context | Supervised pilot trials conducted in two UK residential care homes (NLG and Beverley Grange, Hull). Interactions occurred in typical staff areas with background noise and interruptions. The system operated strictly as a decision-support tool. | Care-home staff interactions | 2 sites | Trial logs, qualitative observations |
| Participants and interaction scenarios | Care staff interacted with the system using natural speech. Scenarios included care documentation, note recording, care information queries, and reminder scheduling. Both scripted and unscripted interactions were included. | Spoken interactions | 330 transcripts | Audio recordings, transcripts, parsed outputs |
| Speech recognition and preprocessing | Whisper-based ASR with signal-quality safeguards and rejection of low-confidence audio segments to prevent unreliable transcriptions. | Spoken input | 330 audio inputs | Accepted/rejected audio segments, ASR transcripts |
| Parsing and database insertion | Transcripts parsed into structured records containing resident ID, care category, timestamp, and free-text notes. Schema validation enforced before insertion into a PostgreSQL database. | ASR transcripts | 330 parsed records | Structured database entries, validation logs |
| Reminder extraction | Reminder descriptions extracted from spoken notes when reminder intent was detected. | Reminder-containing transcripts | 184 cases | Extracted reminder text, classification outputs |
| Retrieval evaluation | Spoken queries issued by care staff and evaluators using sparse, dense, and hybrid retrieval strategies. Needle-in-a-haystack tests embedded critical records within larger document sets. | Trial + synthetic database | 5 representative queries | Retrieved records, ranking positions, similarity scores |
| Metric | Model | Accuracy (%) | CI Lower (%) | CI Upper (%) |
|---|---|---|---|---|
| Category Match | GPT 5.2 | 100 | 98.86 | 100 |
| LLaMA–3 | 97.87 | 95.77 | 99.08 | |
| Qwen | 67.88 | 62.66 | 72.69 | |
| Resident ID Match | GPT 5.2 | 100 | 98.86 | 100 |
| LLaMA–3 | 97.87 | 95.68 | 98.96 | |
| Qwen | 66.36 | 61.10 | 71.25 |
| Model | TP | FP | FN | TN |
|---|---|---|---|---|
| GPT 5.2 | 184 | 36 | 0 | 110 |
| LLaMA–3 | 131 | 0 | 53 | 146 |
| Qwen | 107 | 0 | 77 | 146 |
| Field | Metric | Model | n | Mean | P25 | P75 |
|---|---|---|---|---|---|---|
| Reminder | Cosine Distance | GPT 5.2 | 184 | 0.0743 | 0.0274 | 0.1022 |
| Reminder | Cosine Distance | LLaMA–3 | 127 | 0.1031 | 0.0406 | 0.1410 |
| Reminder | Cosine Distance | Qwen | 106 | 0.1630 | 0.0989 | 0.2013 |
| Reminder | WMD | GPT 5.2 | 184 | 0.3242 | 0.2059 | 0.4460 |
| Reminder | WMD | LLaMA–3 | 127 | 0.4236 | 0.2462 | 0.5690 |
| Reminder | WMD | Qwen | 106 | 0.5476 | 0.4266 | 0.6557 |
| Metric | Model | Accuracy (%) | CI Lower (%) | CI Upper (%) |
|---|---|---|---|---|
| Category Match | GPT 5.2 | 100 | 97.95 | 100.00 |
| LLaMA–3 | 98.18 | 96.09 | 99.16 | |
| Qwen | 67.88 | 60.79 | 74.14 | |
| Resident ID Match | GPT 5.2 | 100 | 97.95 | 100.00 |
| LLaMA–3 | 98.18 | 96.09 | 99.16 | |
| Qwen | 66.36 | 59.25 | 72.79 |
| Method | Metric | Model | Mean |
|---|---|---|---|
| Hybrid RAG | Cosine Distance | GPT 5.2 | 0.371541 |
| LLaMA–3 | 0.428666 | ||
| Qwen | 0.418436 | ||
| Hybrid RAG | WMD Distance | GPT 5.2 | 0.743192 |
| LLaMA–3 | 0.883987 | ||
| Qwen | 0.950280 |
Voice Agent Evaluation
Voice agent evaluation measures how reliably spoken AI systems understand, respond, take actions, and recover in real interactions.
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