Exphormer: Scaling transformers for graph-structured data

Exphormer: Scaling transformers for graph-structured data

Graphs, in which objects and their relations are represented as nodes (or vertices) and edges (or links) between pairs of nodes, are ubiquitous in computing and machine learning (ML). For example, social networks, road networks, and molecular structure and interactions are all domains in which underlying datasets have a natural graph structure. ML can be used to learn the properties of nodes, edges, or entire graphs.

A common approach to learning on graphs are graph neural networks (GNNs), which operate on graph data by applying an optimizable transformation on node, edge, and global attributes. The most typical class of GNNs operates via a message-passing framework, whereby each layer aggregates the representation of a node with those of its immediate neighbors.

Recently, graph transformer models have emerged as a popular alternative to message-passing GNNs. These models build on the success of Transformer architectures in natural language processing (NLP), adapting them to graph-structured data. The attention mechanism in graph transformers can be modeled by an interaction graph, in which edges represent pairs of nodes that attend to each other. Unlike message passing architectures, graph transformers have an interaction graph that is separate from the input graph. The typical interaction graph is a complete graph, which signifies a full attention mechanism that models direct interactions between all pairs of nodes. However, this creates quadratic computational and memory bottlenecks that limit the applicability of graph transformers to datasets on small graphs with at most a few thousand nodes. Making graph transformers scalable has been considered one of the most important research directions in the field (see the first open problem here).

A natural remedy is to use a sparse interaction graph with fewer edges. Many sparse and efficient transformers have been proposed to eliminate the quadratic bottleneck for sequences, however, they do not generally extend to graphs in a principled manner.

In “Exphormer: Sparse Transformers for Graphs”, presented at ICML 2023, we address the scalability challenge by introducing a sparse attention framework for transformers that is designed specifically for graph data. The Exphormer framework makes use of expander graphs, a powerful tool from spectral graph theory, and is able to achieve strong empirical results on a wide variety of datasets. Our implementation of Exphormer is now available on GitHub.

Expander graphs

A key idea at the heart of Exphormer is the use of expander graphs, which are sparse yet well-connected graphs that have some useful properties — 1) the matrix representation of the graphs have similar linear-algebraic properties as a complete graph, and 2) they exhibit rapid mixing of random walks, i.e., a small number of steps in a random walk from any starting node is enough to ensure convergence to a “stable” distribution on the nodes of the graph. Expanders have found applications to diverse areas, such as algorithms, pseudorandomness, complexity theory, and error-correcting codes.

A common class of expander graphs are d-regular expanders, in which there are d edges from every node (i.e., every node has degree d). The quality of an expander graph is measured by its spectral gap, an algebraic property of its adjacency matrix (a matrix representation of the graph in which rows and columns are indexed by nodes and entries indicate whether pairs of nodes are connected by an edge). Those that maximize the spectral gap are known as Ramanujan graphs — they achieve a gap of d – 2*√(d-1), which is essentially the best possible among d-regular graphs. A number of deterministic and randomized constructions of Ramanujan graphs have been proposed over the years for various values of d. We use a randomized expander construction of Friedman, which produces near-Ramanujan graphs.

Expander graphs are at the heart of Exphormer. A good expander is sparse yet exhibits rapid mixing of random walks, making its global connectivity suitable for an interaction graph in a graph transformer model.

Exphormer replaces the dense, fully-connected interaction graph of a standard Transformer with edges of a sparse d-regular expander graph. Intuitively, the spectral approximation and mixing properties of an expander graph allow distant nodes to communicate with each other after one stacks multiple attention layers in a graph transformer architecture, even though the nodes may not attend to each other directly. Furthermore, by ensuring that d is constant (independent of the size of the number of nodes), we obtain a linear number of edges in the resulting interaction graph.

Exphormer: Constructing a sparse interaction graph

Exphormer combines expander edges with the input graph and virtual nodes. More specifically, the sparse attention mechanism of Exphormer builds an interaction graph consisting of three types of edges:

  • Edges from the input graph (local attention)
  • Edges from a constant-degree expander graph (expander attention)
  • Edges from every node to a small set of virtual nodes (global attention)
Exphormer builds an interaction graph by combining three types of edges. The resulting graph has good connectivity properties and retains the inductive bias of the input dataset graph while still remaining sparse.

Each component serves a specific purpose: the edges from the input graph retain the inductive bias from the input graph structure (which typically gets lost in a fully-connected attention module). Meanwhile, expander edges allow good global connectivity and random walk mixing properties (which spectrally approximate the complete graph with far fewer edges). Finally, virtual nodes serve as global “memory sinks” that can directly communicate with every node. While this results in additional edges from each virtual node equal to the number of nodes in the input graph, the resulting graph is still sparse. The degree of the expander graph and the number of virtual nodes are hyperparameters to tune for improving the quality metrics.

Furthermore, since we use an expander graph of constant degree and a small constant number of virtual nodes for the global attention, the resulting sparse attention mechanism is linear in the size of the original input graph, i.e., it models a number of direct interactions on the order of the total number of nodes and edges.

We additionally show that Exphormer is as expressive as the dense transformer and obeys universal approximation properties. In particular, when the sparse attention graph of Exphormer is augmented with self loops (edges connecting a node to itself), it can universally approximate continuous functions [1, 2].

Relation to sparse Transformers for sequences

It is interesting to compare Exphormer to sparse attention methods for sequences. Perhaps the architecture most conceptually similar to our approach is BigBird, which builds an interaction graph by combining different components. BigBird also uses virtual nodes, but, unlike Exphormer, it uses window attention and random attention from an Erdős-Rényi random graph model for the remaining components.

Window attention in BigBird looks at the tokens surrounding a token in a sequence — the local neighborhood attention in Exphormer can be viewed as a generalization of window attention to graphs.

The Erdős-Rényi graph on n nodes, G(n, p), which connects every pair of nodes independently with probability p, also functions as an expander graph for suitably high p. However, a superlinear number of edges (Ω(n log n)) is needed to ensure that an Erdős-Rényi graph is connected, let alone a good expander. On the other hand, the expanders used in Exphormer have only a linear number of edges.

Experimental results

Earlier works have shown the use of full graph Transformer-based models on datasets with graphs of size up to 5,000 nodes. To evaluate the performance of Exphormer, we build upon the celebrated GraphGPS framework [3], which combines both message passing and graph transformers and achieves state-of-the-art performance on a number of datasets. We show that replacing dense attention with Exphormer for the graph attention component in the GraphGPS framework allows one to achieve models with comparable or better performance, often with fewer trainable parameters.

Furthermore, Exphormer notably allows graph transformer architectures to scale well beyond the usual graph size limits mentioned above. Exphormer can scale up to datasets of 10,000+ node graphs, such as the Coauthor dataset, and even beyond to larger graphs such as the well-known ogbn-arxiv dataset, a citation network, which consists of 170K nodes and 1.1 million edges.

Results comparing Exphormer to standard GraphGPS on the five Long Range Graph Benchmark datasets. We note that Exphormer achieved state-of-the-art results on four of the five datasets (PascalVOC-SP, COCO-SP, Peptides-Struct, PCQM-Contact) at the time of the paper’s publication.

<!–

Results comparing Exphormer to standard GraphGPS on the five Long Range Graph Benchmark datasets. We note that Exphormer achieved state-of-the-art results on four of the five datasets (PascalVOC-SP, COCO-SP, Peptides-Struct, PCQM-Contact) at the time of publication.

–><!–

Model   PascalVOC-SP 

 F1 score  
 COCO-SP 

 F1 score  
 Peptides-Func 

 AP  
 Peptides-Struct 

 MAE  
 PCQM-Contact

 MRR
Standard GraphGPS   0.375 ± 0.011   0.341 ± 0.004   0.654 ± 0.004    0.250 ± 0.001   0.334 ± 0.001
Exphormer (ours)   0.398 ± 0.004   0.346 ± 0.001   0.653 ± 0.004   0.248 ± 0.001   0.364 ± 0.002

–>

Finally, we observe that Exphormer, which creates an overlay graph of small diameter via expanders, exhibits the ability to effectively learn long-range dependencies. The Long Range Graph Benchmark is a suite of five graph learning datasets designed to measure the ability of models to capture long-range interactions. Results show that Exphormer-based models outperform standard GraphGPS models (which were previously state-of-the-art on four out of five datasets at the time of publication).

Conclusion

Graph transformers have emerged as an important architecture for ML that adapts the highly successful sequence-based transformers used in NLP to graph-structured data. Scalability has, however, proven to be a major challenge in enabling the use of graph transformers on datasets with large graphs. In this post, we have presented Exphormer, a sparse attention framework that uses expander graphs to improve scalability of graph transformers. Exphormer is shown to have important theoretical properties and exhibit strong empirical performance, particularly on datasets where it is crucial to learn long range dependencies. For more information, we point the reader to a short presentation video from ICML 2023.

Acknowledgements

We thank our research collaborators Hamed Shirzad and Danica J. Sutherland from The University of British Columbia as well as Ali Kemal Sinop from Google Research. Special thanks to Tom Small for creating the animation used in this post.

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Introducing ASPIRE for selective prediction in LLMs

Introducing ASPIRE for selective prediction in LLMs

In the fast-evolving landscape of artificial intelligence, large language models (LLMs) have revolutionized the way we interact with machines, pushing the boundaries of natural language understanding and generation to unprecedented heights. Yet, the leap into high-stakes decision-making applications remains a chasm too wide, primarily due to the inherent uncertainty of model predictions. Traditional LLMs generate responses recursively, yet they lack an intrinsic mechanism to assign a confidence score to these responses. Although one can derive a confidence score by summing up the probabilities of individual tokens in the sequence, traditional approaches typically fall short in reliably distinguishing between correct and incorrect answers. But what if LLMs could gauge their own confidence and only make predictions when they’re sure?

Selective prediction aims to do this by enabling LLMs to output an answer along with a selection score, which indicates the probability that the answer is correct. With selective prediction, one can better understand the reliability of LLMs deployed in a variety of applications. Prior research, such as semantic uncertainty and self-evaluation, has attempted to enable selective prediction in LLMs. A typical approach is to use heuristic prompts like “Is the proposed answer True or False?” to trigger self-evaluation in LLMs. However, this approach may not work well on challenging question answering (QA) tasks.

The OPT-2.7B model incorrectly answers a question from the TriviaQA dataset: “Which vitamin helps regulate blood clotting?” with “Vitamin C”. Without selective prediction, LLMs may output the wrong answer which, in this case, could lead users to take the wrong vitamin. With selective prediction, LLMs will output an answer along with a selection score. If the selection score is low (0.1), LLMs will further output “I don’t know!” to warn users not to trust it or verify it using other sources.

In “Adaptation with Self-Evaluation to Improve Selective Prediction in LLMs“, presented at Findings of EMNLP 2023, we introduce ASPIRE — a novel framework meticulously designed to enhance the selective prediction capabilities of LLMs. ASPIRE fine-tunes LLMs on QA tasks via parameter-efficient fine-tuning, and trains them to evaluate whether their generated answers are correct. ASPIRE allows LLMs to output an answer along with a confidence score for that answer. Our experimental results demonstrate that ASPIRE significantly outperforms state-of-the-art selective prediction methods on a variety of QA datasets, such as the CoQA benchmark.

The mechanics of ASPIRE

Imagine teaching an LLM to not only answer questions but also evaluate those answers — akin to a student verifying their answers in the back of the textbook. That’s the essence of ASPIRE, which involves three stages: (1) task-specific tuning, (2) answer sampling, and (3) self-evaluation learning.

Task-specific tuning: ASPIRE performs task-specific tuning to train adaptable parameters (θp) while freezing the LLM. Given a training dataset for a generative task, it fine-tunes the pre-trained LLM to improve its prediction performance. Towards this end, parameter-efficient tuning techniques (e.g., soft prompt tuning and LoRA) might be employed to adapt the pre-trained LLM on the task, given their effectiveness in obtaining strong generalization with small amounts of target task data. Specifically, the LLM parameters (θ) are frozen and adaptable parameters (θp) are added for fine-tuning. Only θp are updated to minimize the standard LLM training loss (e.g., cross-entropy). Such fine-tuning can improve selective prediction performance because it not only improves the prediction accuracy, but also enhances the likelihood of correct output sequences.

Answer sampling: After task-specific tuning, ASPIRE uses the LLM with the learned θp to generate different answers for each training question and create a dataset for self-evaluation learning. We aim to generate output sequences that have a high likelihood. We use beam search as the decoding algorithm to generate high-likelihood output sequences and the Rouge-L metric to determine if the generated output sequence is correct.

Self-evaluation learning: After sampling high-likelihood outputs for each query, ASPIRE adds adaptable parameters (θs) and only fine-tunes θs for learning self-evaluation. Since the output sequence generation only depends on θ and θp, freezing θ and the learned θp can avoid changing the prediction behaviors of the LLM when learning self-evaluation. We optimize θs such that the adapted LLM can distinguish between correct and incorrect answers on their own.

The three stages of the ASPIRE framework.

In the proposed framework, θp and θs can be trained using any parameter-efficient tuning approach. In this work, we use soft prompt tuning, a simple yet effective mechanism for learning “soft prompts” to condition frozen language models to perform specific downstream tasks more effectively than traditional discrete text prompts. The driving force behind this approach lies in the recognition that if we can develop prompts that effectively stimulate self-evaluation, it should be possible to discover these prompts through soft prompt tuning in conjunction with targeted training objectives.

Implementation of the ASPIRE framework via soft prompt tuning. We first generate the answer to the question with the first soft prompt and then compute the learned self-evaluation score with the second soft prompt.

After training θp and θs, we obtain the prediction for the query via beam search decoding. We then define a selection score that combines the likelihood of the generated answer with the learned self-evaluation score (i.e., the likelihood of the prediction being correct for the query) to make selective predictions.

Results

To demonstrate ASPIRE’s efficacy, we evaluate it across three question-answering datasets — CoQA, TriviaQA, and SQuAD — using various open pre-trained transformer (OPT) models. By training θp with soft prompt tuning, we observed a substantial hike in the LLMs’ accuracy. For example, the OPT-2.7B model adapted with ASPIRE demonstrated improved performance over the larger, pre-trained OPT-30B model using the CoQA and SQuAD datasets. These results suggest that with suitable adaptations, smaller LLMs might have the capability to match or potentially surpass the accuracy of larger models in some scenarios.

When delving into the computation of selection scores with fixed model predictions, ASPIRE received a higher AUROC score (the probability that a randomly chosen correct output sequence has a higher selection score than a randomly chosen incorrect output sequence) than baseline methods across all datasets. For example, on the CoQA benchmark, ASPIRE improves the AUROC from 51.3% to 80.3% compared to the baselines.

An intriguing pattern emerged from the TriviaQA dataset evaluations. While the pre-trained OPT-30B model demonstrated higher baseline accuracy, its performance in selective prediction did not improve significantly when traditional self-evaluation methods — Self-eval and P(True) — were applied. In contrast, the smaller OPT-2.7B model, when enhanced with ASPIRE, outperformed in this aspect. This discrepancy underscores a vital insight: larger LLMs utilizing conventional self-evaluation techniques may not be as effective in selective prediction as smaller, ASPIRE-enhanced models.

Our experimental journey with ASPIRE underscores a pivotal shift in the landscape of LLMs: The capacity of a language model is not the be-all and end-all of its performance. Instead, the effectiveness of models can be drastically improved through strategic adaptations, allowing for more precise, confident predictions even in smaller models. As a result, ASPIRE stands as a testament to the potential of LLMs that can judiciously ascertain their own certainty and decisively outperform larger counterparts in selective prediction tasks.

Conclusion

In conclusion, ASPIRE is not just another framework; it’s a vision of a future where LLMs can be trusted partners in decision-making. By honing the selective prediction performance, we’re inching closer to realizing the full potential of AI in critical applications.

Our research has opened new doors, and we invite the community to build upon this foundation. We’re excited to see how ASPIRE will inspire the next generation of LLMs and beyond. To learn more about our findings, we encourage you to read our paper and join us in this thrilling journey towards creating a more reliable and self-aware AI.

Acknowledgments

We gratefully acknowledge the contributions of Sayna Ebrahimi, Sercan O Arik, Tomas Pfister, and Somesh Jha.

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AMIE: A research AI system for diagnostic medical reasoning and conversations

AMIE: A research AI system for diagnostic medical reasoning and conversations

The physician-patient conversation is a cornerstone of medicine, in which skilled and intentional communication drives diagnosis, management, empathy and trust. AI systems capable of such diagnostic dialogues could increase availability, accessibility, quality and consistency of care by being useful conversational partners to clinicians and patients alike. But approximating clinicians’ considerable expertise is a significant challenge.

Recent progress in large language models (LLMs) outside the medical domain has shown that they can plan, reason, and use relevant context to hold rich conversations. However, there are many aspects of good diagnostic dialogue that are unique to the medical domain. An effective clinician takes a complete “clinical history” and asks intelligent questions that help to derive a differential diagnosis. They wield considerable skill to foster an effective relationship, provide information clearly, make joint and informed decisions with the patient, respond empathically to their emotions, and support them in the next steps of care. While LLMs can accurately perform tasks such as medical summarization or answering medical questions, there has been little work specifically aimed towards developing these kinds of conversational diagnostic capabilities.

Inspired by this challenge, we developed Articulate Medical Intelligence Explorer (AMIE), a research AI system based on a LLM and optimized for diagnostic reasoning and conversations. We trained and evaluated AMIE along many dimensions that reflect quality in real-world clinical consultations from the perspective of both clinicians and patients. To scale AMIE across a multitude of disease conditions, specialties and scenarios, we developed a novel self-play based simulated diagnostic dialogue environment with automated feedback mechanisms to enrich and accelerate its learning process. We also introduced an inference time chain-of-reasoning strategy to improve AMIE’s diagnostic accuracy and conversation quality. Finally, we tested AMIE prospectively in real examples of multi-turn dialogue by simulating consultations with trained actors.

AMIE was optimized for diagnostic conversations, asking questions that help to reduce its uncertainty and improve diagnostic accuracy, while also balancing this with other requirements of effective clinical communication, such as empathy, fostering a relationship, and providing information clearly.

Evaluation of conversational diagnostic AI

Besides developing and optimizing AI systems themselves for diagnostic conversations, how to assess such systems is also an open question. Inspired by accepted tools used to measure consultation quality and clinical communication skills in real-world settings, we constructed a pilot evaluation rubric to assess diagnostic conversations along axes pertaining to history-taking, diagnostic accuracy, clinical management, clinical communication skills, relationship fostering and empathy.

We then designed a randomized, double-blind crossover study of text-based consultations with validated patient actors interacting either with board-certified primary care physicians (PCPs) or the AI system optimized for diagnostic dialogue. We set up our consultations in the style of an objective structured clinical examination (OSCE), a practical assessment commonly used in the real world to examine clinicians’ skills and competencies in a standardized and objective way. In a typical OSCE, clinicians might rotate through multiple stations, each simulating a real-life clinical scenario where they perform tasks such as conducting a consultation with a standardized patient actor (trained carefully to emulate a patient with a particular condition). Consultations were performed using a synchronous text-chat tool, mimicking the interface familiar to most consumers using LLMs today.

AMIE is a research AI system based on LLMs for diagnostic reasoning and dialogue.

AMIE: an LLM-based conversational diagnostic research AI system

We trained AMIE on real-world datasets comprising medical reasoning, medical summarization and real-world clinical conversations.

It is feasible to train LLMs using real-world dialogues developed by passively collecting and transcribing in-person clinical visits, however, two substantial challenges limit their effectiveness in training LLMs for medical conversations. First, existing real-world data often fails to capture the vast range of medical conditions and scenarios, hindering the scalability and comprehensiveness. Second, the data derived from real-world dialogue transcripts tends to be noisy, containing ambiguous language (including slang, jargon, humor and sarcasm), interruptions, ungrammatical utterances, and implicit references.

To address these limitations, we designed a self-play based simulated learning environment with automated feedback mechanisms for diagnostic medical dialogue in a virtual care setting, enabling us to scale AMIE’s knowledge and capabilities across many medical conditions and contexts. We used this environment to iteratively fine-tune AMIE with an evolving set of simulated dialogues in addition to the static corpus of real-world data described.

This process consisted of two self-play loops: (1) an “inner” self-play loop, where AMIE leveraged in-context critic feedback to refine its behavior on simulated conversations with an AI patient simulator; and (2) an “outer” self-play loop where the set of refined simulated dialogues were incorporated into subsequent fine-tuning iterations. The resulting new version of AMIE could then participate in the inner loop again, creating a virtuous continuous learning cycle.

Further, we also employed an inference time chain-of-reasoning strategy which enabled AMIE to progressively refine its response conditioned on the current conversation to arrive at an informed and grounded reply.

AMIE uses a novel self-play based simulated dialogue learning environment to improve the quality of diagnostic dialogue across a multitude of disease conditions, specialities and patient contexts.

We tested performance in consultations with simulated patients (played by trained actors), compared to those performed by 20 real PCPs using the randomized approach described above. AMIE and PCPs were assessed from the perspectives of both specialist attending physicians and our simulated patients in a randomized, blinded crossover study that included 149 case scenarios from OSCE providers in Canada, the UK and India in a diverse range of specialties and diseases.

Notably, our study was not designed to emulate either traditional in-person OSCE evaluations or the ways clinicians usually use text, email, chat or telemedicine. Instead, our experiment mirrored the most common way consumers interact with LLMs today, a potentially scalable and familiar mechanism for AI systems to engage in remote diagnostic dialogue.

Overview of the randomized study design to perform a virtual remote OSCE with simulated patients via online multi-turn synchronous text chat.

Performance of AMIE

In this setting, we observed that AMIE performed simulated diagnostic conversations at least as well as PCPs when both were evaluated along multiple clinically-meaningful axes of consultation quality. AMIE had greater diagnostic accuracy and superior performance for 28 of 32 axes from the perspective of specialist physicians, and 24 of 26 axes from the perspective of patient actors.

AMIE outperformed PCPs on multiple evaluation axes for diagnostic dialogue in our evaluations.
Specialist-rated top-k diagnostic accuracy. AMIE and PCPs top-k differential diagnosis (DDx) accuracy are compared across 149 scenarios with respect to the ground truth diagnosis (a) and all diagnoses listed within the accepted differential diagnoses (b). Bootstrapping (n=10,000) confirms all top-k differences between AMIE and PCP DDx accuracy are significant with p <0.05 after false discovery rate (FDR) correction.
Diagnostic conversation and reasoning qualities as assessed by specialist physicians. On 28 out of 32 axes, AMIE outperformed PCPs while being comparable on the rest.

Limitations

Our research has several limitations and should be interpreted with appropriate caution. Firstly, our evaluation technique likely underestimates the real-world value of human conversations, as the clinicians in our study were limited to an unfamiliar text-chat interface, which permits large-scale LLM–patient interactions but is not representative of usual clinical practice. Secondly, any research of this type must be seen as only a first exploratory step on a long journey. Transitioning from a LLM research prototype that we evaluated in this study to a safe and robust tool that could be used by people and those who provide care for them will require significant additional research. There are many important limitations to be addressed, including experimental performance under real-world constraints and dedicated exploration of such important topics as health equity and fairness, privacy, robustness, and many more, to ensure the safety and reliability of the technology.

AMIE as an aid to clinicians

In a recently released preprint, we evaluated the ability of an earlier iteration of the AMIE system to generate a DDx alone or as an aid to clinicians. Twenty (20) generalist clinicians evaluated 303 challenging, real-world medical cases sourced from the New England Journal of Medicine (NEJM) ClinicoPathologic Conferences (CPCs). Each case report was read by two clinicians randomized to one of two assistive conditions: either assistance from search engines and standard medical resources, or AMIE assistance in addition to these tools. All clinicians provided a baseline, unassisted DDx prior to using the respective assistive tools.

Assisted randomized reader study setup to investigate the assistive effect of AMIE to clinicians in solving complex diagnostic case challenges from the New England Journal of Medicine.

AMIE exhibited standalone performance that exceeded that of unassisted clinicians (top-10 accuracy 59.1% vs. 33.6%, p= 0.04). Comparing the two assisted study arms, the top-10 accuracy was higher for clinicians assisted by AMIE, compared to clinicians without AMIE assistance (24.6%, p<0.01) and clinicians with search (5.45%, p=0.02). Further, clinicians assisted by AMIE arrived at more comprehensive differential lists than those without AMIE assistance.

In addition to strong standalone performance, using the AMIE system led to significant assistive effect and improvements in diagnostic accuracy of the clinicians in solving these complex case challenges.

It’s worth noting that NEJM CPCs are not representative of everyday clinical practice. They are unusual case reports in only a few hundred individuals so offer limited scope for probing important issues like equity or fairness.

Bold and responsible research in healthcare — the art of the possible

Access to clinical expertise remains scarce around the world. While AI has shown great promise in specific clinical applications, engagement in the dynamic, conversational diagnostic journeys of clinical practice requires many capabilities not yet demonstrated by AI systems. Doctors wield not only knowledge and skill but a dedication to myriad principles, including safety and quality, communication, partnership and teamwork, trust, and professionalism. Realizing these attributes in AI systems is an inspiring challenge that should be approached responsibly and with care. AMIE is our exploration of the “art of the possible”, a research-only system for safely exploring a vision of the future where AI systems might be better aligned with attributes of the skilled clinicians entrusted with our care. It is early experimental-only work, not a product, and has several limitations that we believe merit rigorous and extensive further scientific studies in order to envision a future in which conversational, empathic and diagnostic AI systems might become safe, helpful and accessible.

Acknowledgements

The research described here is joint work across many teams at Google Research and Google Deepmind. We are grateful to all our co-authors – Tao Tu, Mike Schaekermann, Anil Palepu, Daniel McDuff, Jake Sunshine, Khaled Saab, Jan Freyberg, Ryutaro Tanno, Amy Wang, Brenna Li, Mohamed Amin, Sara Mahdavi, Karan Sighal, Shekoofeh Azizi, Nenad Tomasev, Yun Liu, Yong Cheng, Le Hou, Albert Webson, Jake Garrison, Yash Sharma, Anupam Pathak, Sushant Prakash, Philip Mansfield, Shwetak Patel, Bradley Green, Ewa Dominowska, Renee Wong, Juraj Gottweis, Dale Webster, Katherine Chou, Christopher Semturs, Joelle Barral, Greg Corrado and Yossi Matias. We also thank Sami Lachgar, Lauren Winer and John Guilyard for their support with narratives and the visuals. Finally, we are grateful to Michael Howell, James Maynika, Jeff Dean, Karen DeSalvo, Zoubin Gharahmani and Demis Hassabis for their support during the course of this project.

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