Whether it’s for patient cohorting, quality reporting, or clinical research, value sets enable accurate data sharing, interoperability, and informed decision-making. In a field as intricate as healthcare, choosing the right approach to creating and managing value sets is essential.
When it comes to value set methodologies, two primary approaches – or types depending on how you look at it – stand out: extensional and intensional. From strict code listings to criteria-based flexibility, the choice between them can significantly influence workflows and outcomes driven by the data included.
Below, we explore these two methodologies and how each one shapes the landscape of healthcare data, impacting everything from ease of maintenance to the effectiveness of clinical decision support.
Extensional value sets
An extensional value set is a collection of explicitly listed codes that match inclusion and exclusion criteria exactly. The set is specified by directly enumerating all its members rather than by providing a rule or property that the members must satisfy. Think of them like a hand-picked playlist of songs – every code is individually selected to fit a particular purpose or criteria, without any additions beyond what was specifically chosen.
Extensional value sets are particularly useful when there’s a need for precise control over the codes included. For example, consider a value set created for tracking and managing cases of gestational diabetes. This extensional list would include a carefully chosen selection of ICD-10-CM codes: O24.410, O24.414, O24.415, O24.419, O24.420, O24.424, O24.425, O24.429, O24.430, O24.434, O24.435, and O24.439.
Each code is specifically selected to cover various aspects of gestational diabetes and exclude any irrelevant codes, helping maintain consistent, accurate data collection for reporting or quality assurance.
These curated lists are often essential in scenarios like quality reporting and billing, where meeting regulatory or reimbursement requirements demands clear and specific references to individual codes.
Benefits of extensional value sets
By precisely selecting each code, users can be sure of exactly what’s included, making it easier to maintain uniformity across systems or applications. Other benefits include:
- Precision: Allows for explicit control over exactly which codes are included
- Consistency: Easier to maintain uniformity across systems and applications
- Relevance: Ensures that each selected code aligns with the specific criteria or use case
- Clarity: Clear, unambiguous lists are ideal for regulatory, quality, or billing requirements
- Ease of auditing: Directly enumerated codes make the set straightforward to review or audit
- Reduced ambiguity: Specific codes limit interpretation errors in clinical, billing, and reporting contexts
Drawbacks of extensional value sets
Despite these strengths, extensional value sets present some challenges:
- Static nature: Requires frequent manual updates to remain current
- Scalability issues: Becomes cumbersome as code systems change and expand
- Maintenance costs: Ongoing updates drive up resource costs
- Risk of omission or redundancy: Manual selection may lead to incomplete or redundant codes
- Increased data size and inefficiency: Large lists can become hard to manage
- Handling complex concepts: Limited flexibility for nuanced clinical relationships
- Limited generalization and reusability: Hard to adapt for different applications
Intensional value sets
An intensional value set is defined by a rule or set of rules that determines “membership” rather than listing each code/member explicitly. This approach is like a music streaming service that curates a playlist or station for you, algorithmically selecting songs from a particular genre or by a certain artist, then adjusting automatically as new songs are released or as it learns more. With intensional value sets, codes that meet specified criteria are dynamically included, making it a flexible and adaptive approach that aligns with evolving clinical standards.
Intensional value sets are especially useful when managing large, complex code systems that need to stay current with minimal maintenance. For instance, an intensional value set designed to capture all codes related to gestational diabetes could be defined by a rule like, “Include all children of code O24.4” in ICD-10-CM. This rule would automatically encompass all relevant gestational diabetes codes. Any new, related codes added to the system would be captured automatically, ensuring the value set remains up to date without intervention.
Intensional value sets are ideal for situations requiring scalability and adaptability, such as population health or large-scale research studies, where it’s critical to synchronize data with the latest medical information across diverse and expansive datasets.
Benefits of intensional value sets
Intensional value sets offer several advantages that make them a popular choice in many healthcare applications:
- Flexibility: Updates automatically as the underlying code system evolves, reducing the need for manual adjustments
- Scalability: Efficiently handles large code systems by defining membership through criteria rather than specific codes
- Efficient maintenance: Defined by rules, so there’s less need for manual updating as new versions of code systems are released
- Simplified representation: Concise rules simplify documentation, communication, and understanding, especially in complex cases
- Reduced redundancy: Avoids the risk of duplicating or missing members by using rules rather than a static list
- Lower error risk: Prevents accidental omissions or duplications, helping maintain accuracy
- Cost and time efficiency: Rules minimize the need for extensive manual labor in set creation and upkeep
Drawbacks of intensional value sets
Despite their many benefits, intensional value sets do come with some limitations:
- Less control: Organizations may not always know exactly which codes are included at any given moment
- Over-inclusiveness: Depending on the logic, these value sets could pull in unrelated codes, impacting specificity
- Harder to audit: Rule-based memberships can make it difficult to review and validate over time
- Complexity in setup: Creating accurate rules can be challenging, especially for nuanced clinical criteria
Leveraging value set variation for better data quality in healthcare
While extensional sets offer precision and control, intensional sets provide flexibility and scalability—qualities essential for keeping pace with evolving clinical standards and coding updates. Moving forward, organizations need a hybrid approach, strategically using both types to support varied data needs across quality reporting, research, and clinical care.
IMO Precision Sets delivers just that, balancing flexibility and accuracy, ensuring that value sets remain robust, relevant, and easy to maintain over time. By choosing tools that support both extensional and intensional approaches, organizations can better meet current data demands while preparing for the needs of tomorrow.
