The Evolution of the Level of Accuracy (LOA) Specification
The Level of Accuracy (LOA) Specification, developed by the U.S. Institute of Building Documentation (USIBD), has become an indispensable tool for building documentation. Since its inception, the LOA has addressed a critical gap: the lack of a recognized standard for specifying accuracy in building documentation. With the upcoming release of Version 3.1 in January 2025 (Figure 1), the LOA continues to evolve, incorporating minor but meaningful enhancements to meet the ever-growing demands of the architecture, engineering, construction, operations (AECO), and historic preservation industries.
Figure 1: Cover of the LOA v3.1 Specification Guide
A brief history of the LOA
The LOA has a storied history, dating back to the release of Version 1.0 in 2014. At the time, there was no universally accepted framework for defining the accuracy of measurements and representations in building documentation. Recognizing this gap, the USIBD formed the LOA Subcommittee under its Standards Committee to address the industry’s needs.
Drawing inspiration from recognized standards such as the AIA/BIM Forum’s Level of Development (LOD) Specification, CSI’s UniFormat™, and the German Institute for Standardization’s DIN 18710, the LOA was designed to promote interoperability between existing frameworks, filling a critical void. While the LOD focuses on defining the development level of a Building Information Model (BIM), it does not address the accuracy of the data underlying that model. The LOA bridges this gap, ensuring both measured accuracy and represented accuracy are explicitly defined and met.
The LOA Specification has seen global acceptance, with professionals from diverse industry sectors contributing to its development. It remains the most downloaded document on the USIBD website, reflecting its widespread adoption and utility.
What makes the LOA unique?
The LOA is built around the philosophy that “Intent Defines Process,” a guiding principle articulated by USIBD. This emphasizes that accuracy is not just a technical requirement, but a deliberate decision tied to the project’s goals. By defining the intent of a project, practitioners can identify the means and methods to achieve the required accuracy.
Figure 2: Level of Accuracy ranges in metric and imperial units.
The LOA framework incorporates five levels of accuracy: LOA10, LOA20, LOA30, LOA40, and LOA50 (Figure 2). These levels correspond to increasingly stringent ranges of tolerance, inspired by the five tolerance ranges defined in the DIN 18710 standard. The LOA also introduces the dual concepts of Measured Accuracy (accuracy of the data collected) and Represented Accuracy (accuracy of the models or drawings derived from the data).
This dual approach acknowledges the additional errors introduced during data representation.
Structured using the Metric System (with imperial conversions), the LOA ensures compatibility with global practices while accommodating the needs of the U.S. market. The Specification Guide and accompanying Specification Framework spreadsheet provide practitioners with practical tools to define and document accuracy requirements for their projects.
What’s new in LOA Version 3.1?
The release of LOA Version 3.1 in early 2025 marks a minor upgrade to Version 3.0, which was introduced in 2019. While the changes may be subtle, they are designed to enhance usability and clarity. There are four key enhancements.
- Graphical updates: Improved visual elements throughout the document enhance readability and comprehension, such as those in Figures 3 and 4.
- Simplified tolerance computation: Previous versions included detailed narratives on relative measurement tolerances (e.g., squared vs. linear approaches). These have been replaced with a practical method for converting between tolerance and standard deviation. This change aligns the LOA with common field measurement practices and ensures compatibility with fabrication standards, which often require tolerances.
- Improved readability: Copy edits have been made throughout the document to clarify technical language and improve understanding for a broader audience.
- Practical guidance for professionals: The new method for converting between tolerance and standard deviation ensures professionals can confidently meet accuracy requirements, regardless of whether a project specifies tolerances or standard deviations.
These changes reflect USIBD’s commitment to making the LOA a living document, one that evolves to meet the needs of practitioners while maintaining its foundational principles.
Figure 3: Precision, correctness and accuracy.
Figure 4: Measured and Represented Accuracy with LOA Levels.
USIBD’s new Education Center
In addition to the updated LOA, the USIBD is proud to unveil its new Education Center, a milestone initiative aimed at fostering professional growth and standardizing best practices in the building documentation industry. The Education Center will offer on-demand training and certification programs, starting with a course and certification focused on the LOA.
In addition to LOA training and certification, USIBD’s Education Center will serve as a dynamic platform for ongoing professional development. The introduction of the LOA training is just the beginning. The Education Center will continually expand its library of coursework, building a comprehensive foundation that will support the eventual rollout of Building Documentation Professional (BDP) and Building Documentation Technologist (BDT) certifications.
These certifications represent USIBD’s commitment to establishing a structured pathway for industry practitioners to achieve recognition for their expertise. As new courses are added, they will address key areas of building documentation, from advanced measurement techniques to best practices in data management and integration with BIM workflows. This evolving curriculum is designed to equip professionals with the skills and knowledge necessary to meet the challenges of a rapidly advancing industry.
The BDP and BDT certifications will be pivotal milestones in the professionalization of building documentation, offering practitioners a way to demonstrate their qualifications and stand out in a competitive market. By laying the groundwork now, USIBD is creating a future where excellence in building documentation is both measurable and recognized.
Why the LOA matters
The LOA continues to fill a critical role in the industry. As building documentation technologies evolve, so too must the standards that govern them. The LOA’s integration with complementary frameworks such as the LOD Specification and CSI’s UniFormat™ ensures its relevance and utility. Moreover, the LOA’s commitment to interoperability and practicality makes it a trusted resource for professionals worldwide.
While other guidelines may attempt to define accuracy schemas, the LOA remains the most widely recognized and accepted standard for building documentation. By incorporating input from industry professionals and aligning with global practices, USIBD has created a standard that is not only technically sound but also universally applicable.
Get involved with USIBD
USIBD’s success is rooted in the dedication of its members and the collaborative spirit of the building documentation community. As the LOA and the Education Center continue to evolve, USIBD invites professionals to join its committees and contribute to the development of industry standards.
Membership in USIBD offers opportunities to shape the future of building documentation, network with industry leaders, and access valuable resources, including the free download of the LOA.
Conclusion
The upcoming release of LOA Version 3.1 and the launch of the USIBD Education Center represent significant milestones for the building documentation industry. These initiatives underscore USIBD’s commitment to advancing standards, fostering professional growth, and supporting the building documentation community.
Whether you are a seasoned professional or new to building documentation, the LOA provides a framework for achieving accuracy and precision in your projects. Download the LOA Specification for free from the USIBD website and explore the new Education Center to take your expertise to the next level. Together, we can continue to shape the future of building documentation. 
John M. Russo is the visionary founder of Architectural Resource Consultants (ARC), a pioneering firm specializing in professional building documentation services since 1997. With a career dating back to 1984, Mr. Russo’s passion for precise as-built documentation and facility life-cycle solutions has driven ARC to become an award-winning industry leader.
In 2011, he founded the U.S. Institute of Building Documentation (USIBD), a non-profit committed to advancing excellence in building documentation, and served on the Board of Directors and as President for twelve years. Currently, he holds an advisory role as Board Member Emeritus. He is also a member of the BIM Forum Working Group Advisory Board.
Mr. Russo delivers keynote addresses and is a featured speaker at major shows and conferences. He has published widely in many journals and newsletters.
Mr. Russo holds a BA in business administration from California State University, Fullerton, and an AA in Architecture from Orange Coast College. As a registered architect in California, his wealth of experience and unwavering commitment to excellence continue to shape and elevate the building documentation industry under his leadership.