What is a Unique Identifier (UID)?

Posted by Mike Woods

Fixed Asset Market Manager

in Inventory Management

Updated May 28th, 2024

Table of Contents

• What is a UID?
• What is the UID Program?
• What is the Difference Between UID, IUID, UII?
• Important Facts about UID
• The 2 Main Benefits of a UID
• Final Thoughts on UIDs
• Frequently Asked Questions

In today’s complex systems and operations, the ability to uniquely identify and track assets or entities is paramount. This critical need has led to the widespread adoption of Unique Identifiers (UIDs) – distinct codes or numbers assigned to individual items or entities.

UIDs play a vital role in ensuring accurate identification, traceability, and efficient management across various industries, including manufacturing, supply chain, healthcare, and the military. The implementation of UIDs enables organizations to maintain precise records, streamline inventory management, enhance operational efficiency, and ensure compliance with regulatory requirements.

In manufacturing, UIDs facilitate quality control and traceability from component sourcing to final products. The healthcare sector leverages UIDs for medical devices, implants, and pharmaceuticals to safeguard patient safety.

Moreover, the military has been at the forefront of adopting UIDs, employing them to track a wide range of equipment, from vehicles to munitions, ensuring precise inventory management and strategic deployment readiness.

What is a UID?

A unique identifier (UID), also known as IUID, is a program originated by the Department of Defense (DOD) to provide better accountability for their tangible assets. This program requires that a unique and specific number be assigned to Government owned and Government purchased tangible equipment according to established rules.

This number is then applied to the asset or marked directly on the asset for its useful life.  The actual number is referred to as the UII or unique item identifier which is globally unique by design.

What is the UID Program?

The Unique Identification Program was established by memorandum in 2004 and then detailed in subsequent versions of MIL-STD- 130.  Later, the program was mandated to owners and manufacturers of Government Defense related equipment.  The mandate created implementation plans for Government entities as well as a contract clause for manufacturers, (DFARS) clause 252-211-7003.

The central characteristic of ID is the presentation of the UII in a 2D bar code called a data matrix code.  This is a square or rectangular symbol read with a digital imager.  This differs from the string of bars and spaces most people are used to seeing.

What is the Difference Between UID, IUID, UII?

The Defense Procurement and Acquisition Policy offers some key definitions that clarify the differences between UID, IUID, and UII.

• UID/IUID: “A system of establishing globally unique and unambiguous identifiers within the Department of Defense, which serve to distinguish a discrete entity or relationship from other like and unlike entities or relationships. (Ref: MIL-STD-130N Change 1).”
• UII (unique item identifier): “A globally unique and unambiguous identifier that distinguishes an item from all other like and unlike items. The UII is derived from a UII data set of one or more data elements. (Ref: MIL-STD-130N Change 1).”

MIL-STD-130 provides uniform engineering and technical requirements concerning processes, procedures, practices, and methods.  MIL-STD-130, specifically, addresses standard practices for identification marking for U.S. military property, both for UID applications and for non-UID applications.

Important Facts about UID

UID is required by the U.S. Department of Defense for all equipment with an acquisition cost exceeding $5,000, as well as mission-critical equipment, controlled inventory, serially-controlled equipment, and consumable equipment.

2D Data Matrix ECC 200 Symbol is the required technology used in marking individual items to allow them to be machine readable or “scanned.” The Department of Defense requires UID for all solicitations received on or after January 1, 2005.

Additionally, the DOD has mandated that all federal contractors have UID markings on government-furnished military and non-military equipment. Items are not eligible for IUID registry until they have UID markings with unique item identifiers.

The 2 Main Benefits of a UID

There are two primary benefits of UID:

1. First, the globally unique, unambiguous identifier virtually eliminates confusion among assets in databases and reduces duplication of assets records.
2. Second, the data matrix code allows electronic capturing of the item identifier.  This eliminates slow, cumbersome, and error prone manual entries into systems.

UID provides both improved data integrity and data quality throughout the life of assets. Contributing to this is the requirement that UID labels and marks must remain readable throughout the life of assets.

Marking materials and processes must now withstand harsh environments and extended outdoor conditions, thus placing new emphasis on marking methods and material choices.

Final Thoughts on UIDs

The increased productivity and efficiency offered by UID provides cost-savings benefits to both the DOD, federal contractors, and taxpayers. The individual item data proves useful for logistics and engineering analysis, thus enabling the identification of further cost-savings opportunities. 

Finally, a unique identifier also provides in-depth historical data tracing of individual assets from design and production through asset retirement and disposal.

Frequently Asked Questions