--- title: "Locked vs. Adaptive Algorithm, Definition | MedTech Terms" description: "Distinction between models whose behavior is fixed at release vs. those that continue learning. Plain-English Software & AI definition for MedTech teams, with e" lang: en json-ld: | { "@context": "https://schema.org", "@graph": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/locked-vs-adaptive#term", "name": "Locked vs. Adaptive Algorithm", "description": "A locked algorithm produces the same output for the same input every time after release. An adaptive algorithm changes its behavior over time as it is exposed to new data, either continuously or in scheduled retraining cycles.", "url": "https://medtechterms.com/terms/locked-vs-adaptive", "termCode": "locked-vs-adaptive", "inDefinedTermSet": { "@type": "DefinedTermSet", "name": "MedTech Terms", "url": "https://medtechterms.com/terms" } }, { "@type": "Article", "@id": "https://medtechterms.com/terms/locked-vs-adaptive#article", "headline": "Locked vs. Adaptive Algorithm", "description": "Distinction between models whose behavior is fixed at release vs. those that continue learning.", "url": "https://medtechterms.com/terms/locked-vs-adaptive", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://medtechterms.com/terms/locked-vs-adaptive" }, "about": { "@id": "https://medtechterms.com/terms/locked-vs-adaptive#term" }, "articleSection": "Software & AI", "inLanguage": "en", "keywords": "Locked vs. Adaptive Algorithm, Software & AI, medical device, MedTech", "author": { "@type": "Person", "name": "Christian Espinosa", "jobTitle": "Founder, Blue Goat Cyber", "url": "https://bluegoatcyber.com" }, "publisher": { "@type": "Organization", "name": "MedTech Terms", "url": "https://medtechterms.com" }, "isPartOf": { "@type": "WebSite", "name": "MedTech Terms", "url": "https://medtechterms.com" }, "datePublished": "2026-05-05", "dateModified": "2026-05-05", "citation": [ { "@type": "CreativeWork", "name": "MDCG Software Guidance", "url": "https://health.ec.europa.eu/medical-devices-sector/new-regulations/guidance-mdcg-endorsed-documents-and-other-guidance_en", "publisher": { "@type": "Organization", "name": "MDCG" } }, { "@type": "CreativeWork", "name": "FDA - Software as a Medical Device (SaMD)", "url": "https://www.fda.gov/medical-devices/digital-health-center-excellence/software-medical-device-samd", "publisher": { "@type": "Organization", "name": "FDA" } }, { "@type": "CreativeWork", "name": "FDA - AI/ML-Enabled Medical Devices", "url": "https://www.fda.gov/medical-devices/software-medical-device-samd/artificial-intelligence-and-machine-learning-aiml-enabled-medical-devices", "publisher": { "@type": "Organization", "name": "FDA" } } ], "mentions": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/ai-ml-pccp#term", "name": "Predetermined Change Control Plan", "alternateName": "PCCP", "url": "https://medtechterms.com/terms/ai-ml-pccp" }, { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/ai-ml-device#term", "name": "AI/ML-Enabled Medical Device", "url": "https://medtechterms.com/terms/ai-ml-device" }, { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/good-machine-learning-practice#term", "name": "Good Machine Learning Practice", "alternateName": "GMLP", "url": "https://medtechterms.com/terms/good-machine-learning-practice" } ] }, { "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://medtechterms.com/" }, { "@type": "ListItem", "position": 2, "name": "Terms", "item": "https://medtechterms.com/terms" }, { "@type": "ListItem", "position": 3, "name": "Software & AI", "item": "https://medtechterms.com/terms?cat=Software%20%26%20AI" }, { "@type": "ListItem", "position": 4, "name": "Locked vs. Adaptive Algorithm", "item": "https://medtechterms.com/terms/locked-vs-adaptive" } ] }, { "@type": "FAQPage", "@id": "https://medtechterms.com/terms/locked-vs-adaptive#faq", "mainEntity": [ { "@type": "Question", "name": "Can an adaptive algorithm ever become a locked algorithm?", "acceptedAnswer": { "@type": "Answer", "text": "Yes, an adaptive algorithm might be 'locked' at a specific version after extensive validation, especially if its environment stabilizes or further adaptation introduces undue risk. This transition typically requires clear documentation and justification." } }, { "@type": "Question", "name": "What is the primary regulatory concern with adaptive algorithms?", "acceptedAnswer": { "@type": "Answer", "text": "The primary regulatory concern is ensuring safety and effectiveness are maintained as the algorithm evolves. This involves controlling the types of changes, monitoring performance, and managing potential biases or unintended behaviors introduced by new data." } }, { "@type": "Question", "name": "How does the EU MDR address adaptive algorithms?", "acceptedAnswer": { "@type": "Answer", "text": "The EU MDR categorizes all software as medical devices, and adaptive algorithms fall under these regulations, requiring manufacturers to demonstrate conformity with Annex I General Safety and Performance Requirements. The focus is on robust quality management systems, risk management, and clinical evaluation throughout the device's lifecycle, including any post-market changes." } }, { "@type": "Question", "name": "What role does real-world performance monitoring play for adaptive algorithms?", "acceptedAnswer": { "@type": "Answer", "text": "Real-world performance monitoring is crucial for adaptive algorithms to detect performance drift, identify new biases, and ensure the algorithm continues to meet its intended purpose safely and effectively over time. This data often informs retraining cycles and risk assessments." } } ] } ] } --- [ MedTech Terms The authoritative reference ](/) Browse Learn [Latest](/latest) About 1. [Home](/) 2. / 3. [Terms](/terms) 4. / 5. [Software & AI](/terms?cat=Software%20%26%20AI) 6. / 7. Locked vs. Adaptive Algorithm [All terms](/terms) Software & AI [AI / ML in Devices](/ecosystems/ai-ml)[Software Lifecycle](/ecosystems/software-lifecycle) # Locked vs. Adaptive Algorithm Distinction between models whose behavior is fixed at release vs. those that continue learning. Reviewed by [Christian Espinosa, Founder, Blue Goat Cyber](/authors/christian-espinosa) Last reviewed May 5, 2026 ## Definition A locked algorithm produces the same output for the same input every time after release. An adaptive algorithm changes its behavior over time as it is exposed to new data, either continuously or in scheduled retraining cycles. What the regulation says The FDA's guidance, ' [Good Machine Learning Practice](/terms/good-machine-learning-practice) for Medical Device Development' and the ' [Predetermined Change Control Plan](/terms/ai-ml-pccp)' (PCCP) framework, differentiates between locked and adaptive algorithms. For locked algorithms, regulatory review focuses on the algorithm's performance at the time of submission. For adaptive algorithms, regulators assess the manufacturer's control over the modification protocol, the ' [Algorithm Change Protocol](/terms/algorithm-change-protocol),' to ensure predictable and [safe](/terms/safe-note) evolution. ## What this means in practice FDA's [PCCP](/terms/ai-ml-pccp) framework lets manufacturers prospectively define and validate the boundaries of allowable adaptive changes so retraining does not require a new submission for each model update. ## Examples - A diagnostic AI that learns to identify new patterns in medical images as it processes more patient scans is an adaptive algorithm requiring a PCCP. - An insulin pump algorithm that adjusts dosing recommendations based on a patient's continuously acquired glucose data and activity levels is an adaptive algorithm. - A risk stratification tool that uses a fixed set of patient demographics and historical health records to predict disease likelihood is a locked algorithm. Common pitfalls - • Failing to establish clear performance bounds and risk mitigations for adaptive algorithm changes can lead to regulatory non-compliance. - • Treating an adaptive algorithm as a locked algorithm for validation purposes will result in insufficient oversight of its evolving behavior. - • Not documenting the data used for training and retraining, along with corresponding version control, can create significant auditability issues. - • Assuming all adaptive algorithm changes are minor and do not impact safety or effectiveness can lead to patient harm and regulatory scrutiny. ## Frequently asked questions Can an adaptive algorithm ever become a locked algorithm? Yes, an adaptive algorithm might be 'locked' at a specific version after extensive validation, especially if its environment stabilizes or further adaptation introduces undue risk. This transition typically requires clear documentation and justification. What is the primary regulatory concern with adaptive algorithms? How does the EU MDR address adaptive algorithms? What role does real-world performance monitoring play for adaptive algorithms? ## Cross-references ### Uses Concepts or artefacts this term builds on. - [ Predetermined Change Control Plan(PCCP) ](/terms/ai-ml-pccp) ## Related terms Grouped by theme ### Editor's picks · Hand-selected related concepts [ Software & AI AI/ML-Enabled Medical Device Medical device that uses artificial intelligence or machine learning to perform its intended use. ](/terms/ai-ml-device)[ Software & AI Good Machine Learning Practice(GMLP) Guiding principles for the development of AI/ML-enabled medical devices. ](/terms/good-machine-learning-practice)[ Software & AI Predetermined Change Control Plan(PCCP) FDA mechanism to pre-authorize specific modifications to AI/ML-enabled devices. ](/terms/ai-ml-pccp) ### More in Software & AI · Same category [ Software & AI AAMI TIR45(TIR45) AAMI Technical Information Report providing guidance on applying Agile software development practices within an IEC 62304-compliant medical device software lifecycle. ](/terms/aami-tir45)[ Software & AI Adversarial Robustness Resilience of an ML model to inputs deliberately crafted to cause misclassification. ](/terms/adversarial-robustness)[ Software & AI Algorithm Change Protocol(ACP) The detailed procedural section of a PCCP that specifies how planned modifications to an AI/ML model will be developed, validated, and implemented. ](/terms/algorithm-change-protocol)[ Software & AI Algorithmic Bias and Fairness Systematic differences in model performance across demographic or clinical subgroups. ](/terms/ai-bias-fairness) Cited by Where this term appears across MedTech Terms. Ecosystems (2) - [AI / ML in Devices](/ecosystems/ai-ml) - [Software Lifecycle](/ecosystems/software-lifecycle) ## Primary references 3 sources Link health: 3 verified · last checked 2026-06-20 MDCG· 1 FDA· 2 1. [1 MDCG Software Guidance Verified MDCG · health.ec.europa.eu ](https://health.ec.europa.eu/medical-devices-sector/new-regulations/guidance-mdcg-endorsed-documents-and-other-guidance_en) 2. [2 FDA - Software as a Medical Device (SaMD) Verified FDA · fda.gov ](https://www.fda.gov/medical-devices/digital-health-center-excellence/software-medical-device-samd) 3. [3 FDA - AI/ML-Enabled Medical Devices Verified FDA · fda.gov ](https://www.fda.gov/medical-devices/software-medical-device-samd/artificial-intelligence-and-machine-learning-aiml-enabled-medical-devices) Inline markers like \[1\] jump to the matching reference above. Sponsor note ### Building software-as-a-medical-device? We help SaMD and AI/ML device teams meet IEC 62304 and the FDA's evolving expectations for software cybersecurity. [Book a 30-minute discovery session](https://go.bluegoatcyber.com/meetings/blue-goat-cyber/discovery-session) - No obligation - Expert-led from minute one - NDA available on request MedTech Terms is a community resource sponsored by [Blue Goat Cyber](https://bluegoatcyber.com). Definitions are independent of any vendor. On this term Category Software & AI Sources 3 Updated 5/5/2026 [Compare with another term](/compare?a=locked-vs-adaptive) Learn in 60 seconds Card Lesson Quiz Distinction between models whose behavior is fixed at release vs. those that continue learning. - · FDA's PCCP framework lets manufacturers prospectively define and validate the boundaries of allowable adaptive changes so retraining does not require a new submission for each model update. - · An adaptive algorithm changes its behavior over time as it is exposed to new data, either continuously or in scheduled retraining cycles. Remember this Watch out: Failing to establish clear performance bounds and risk mitigations for adaptive algorithm changes can lead to regulatory non-compliance. Related terms - [Predetermined Change Control Plan(PCCP) ](/terms/ai-ml-pccp) - [AI/ML-Enabled Medical Device ](/terms/ai-ml-device) - [Good Machine Learning Practice(GMLP) ](/terms/good-machine-learning-practice) You may also need Auto-suggested from Software & AI and shared keywords. - [Model Drift Monitoring ](/terms/drift-monitoring) - [Predetermined Maintenance vs PCCP ](/terms/predetermined-maintenance) - [Algorithm Change Protocol(ACP) ](/terms/algorithm-change-protocol) - [MLOps for Medical Devices(MLOps) ](/terms/mlops-medical-device) - [Software Maintenance Plan ](/terms/software-maintenance-plan) - [Data Governance (AI/ML) ](/terms/data-governance) [All Software & AI terms](/terms?cat=Software%20%26%20AI) From the Blue Goat network Related resources and services on this topic. - [ AI SaMD Insights How AI is changing SaMD - risk, regulation, and good machine-learning practice. ](https://ai-samd.com) - [ Med Device Cyber Podcast Conversations with medical device cybersecurity practitioners. ](https://mdcpodcast.com) MedTech Terms An authoritative, plain-language reference for the regulatory, quality, cybersecurity, and software terms that shape modern medical devices. Browse - [All terms](/terms) - [A–Z index](/a-z) - [Categories](/categories) - [Ecosystems](/ecosystems) - [Learning paths](/paths) - [Compare terms](/compare) - [Quiz](/quiz) Resources - [FDA Medical Devices](https://www.fda.gov/medical-devices) - [EU MDR](https://eur-lex.europa.eu/eli/reg/2017/745/oj) - [IMDRF](https://www.imdrf.org/) - [Methodology](/methodology) - [Changelog](/changelog) - [Editor: Christian Espinosa](/authors/christian-espinosa) - [About this site](/about) © 2026 MedTech Terms. Reference content for educational purposes - not regulatory advice. A community resource sponsored by [Blue Goat Cyber](https://bluegoatcyber.com)