Understanding Disambiguation with Philterd Data Services

The Philterd Team

December 31, 2025

Understanding Disambiguation with Philterd Data Services

First up - What Is Philterd Data Services?

Philterd Data Services is a comprehensive platform designed to help organizations identify, protect, and manage sensitive information, particularly Personally Identifiable Information (PII) and Protected Health Information (PHI). It offers capabilities for automated redaction, risk assessment, and compliance-ready processing of files such as PDF, DOCX, and plain text.

All operations are performed within Philterd’s infrastructure, with no third-party involvement, and users retain control over what is redacted and how those redactions are applied. The platform supports a full API as well as a dashboard for inspection, audit logs, and usage tracking.

At its core, Philterd Data Services enables organizations to define redaction policies that determine what types of sensitive information should be detected and how they should be handled - including masking, encryption, anonymization, or other redaction strategies specified by the customer’s compliance requirements.

The Challenge of Ambiguities in Redaction

When sensitive information is detected in text, multiple filters may identify overlapping or conflicting spans of text. For example, a sequence of digits might be interpreted as either a phone number or a social security number, depending on the context. Similarly, a text like “Washington” could represent a person’s name, a location, or an organization. In such cases, a decision must be made about which interpretation is most accurate for redaction purposes.

This problem happens when a span of text could correspond to more than one classification. This is problem is called disambiguation. Without an effective resolution strategy, redaction can be incorrect, either missing sensitive data or over-redacting non-sensitive content.

What Is Disambiguation in Philterd Data Services?

In Philterd Data Services, disambiguation refers to the process of resolving overlapping or conflicting identifications made by redaction filters. Its goal is to ensure that redactions are both accurate and contextually appropriate, reducing false positives and negatives during automated document processing.

When Philterd scans a document, each potential sensitive span is assigned a confidence score and analyzed in context. Disambiguation strategies account for span length, confidence levels, and the text surrounding a span to determine the best classification for that instance of text.

Disambiguation Scopes: Document vs. Context

A key configuration option in Philterd Data Services redaction policies is the disambiguation scope. The disambiguation scope determines how the system applies contextual information when resolving ambiguities. There are two possible scope settings:

1. Document Scope

With document-level disambiguation, the system considers only the information within the single document currently being processed when resolving overlapping or ambiguous spans. This mode is efficient and suitable when you need consistent processing on a per-document basis—for example, when documents are independent from one another and no shared context is required.

2. Context Scope

With context-level disambiguation, Philterd Data Services uses information from all documents within the same redaction context to resolve ambiguities. A “context” may consist of a batch of related documents or an ongoing workflow where patterns of sensitive information appear across multiple files. As more documents are processed under the same context, the system can leverage accumulated insights to make more informed decisions about ambiguous spans, potentially improving accuracy over time.

To summarize disambiguation scope:

Document scope treats each document independently.
Context scope lets the engine “learn” or adapt across documents by considering broader evidence when disambiguating.

Choosing the appropriate scope depends on your organization’s workflow and how your data is structured. Context scope is particularly valuable in scenarios with related texts (e.g., series of reports, medical records, legal briefs), whereas document scope may suffice for stand-alone files or when performance is a priority.

How Disambiguation Fits Into Redaction Policies

Within a redaction policy, the disambiguation scope is just one configurable element. Policies also allow you to specify confidence thresholds (to filter out low-confidence detections), custom rules for specific identifiers, and how redactions should be applied (e.g. masked, encrypted, anonymized)

Effective disambiguation ensures that policies operate on a solid foundation: accurate classification of sensitive spans. For example, if a span is ambiguous between an address and a person’s name, context scope may help the model decide which label fits best based on how similar spans have appeared in related documents processed under the same context.

Conclusion

Disambiguation is a crucial capability for any automated redaction platform. Without it, conflicting or overlapping identifications of sensitive data can lead to errors in compliance and privacy protection. Philterd Data Services addresses this challenge with configurable disambiguation scopes that give users a way to balance performance with contextual accuracy. By choosing between document-level and context-level disambiguation, organizations can tailor redaction behavior to their workflows and achieve more reliable results across diverse data sets.

Whether you are handling individual documents or large batches of related records, understanding and controlling disambiguation can significantly enhance your data protection strategy with Philterd Data Services.