Technology Readiness Levels (TRL) are a method of estimating the technology maturity of Critical Technology Elements (CTE) of a program during the acquisition process. They are determined during a Technology Readiness Assessment (TRA) that examines program concepts, technology requirements and demonstrated technology capabilities.
Definition: Technology Readiness Levels (TRL) are a method used to measure and assess the maturity of a particular technology. They allow engineers, managers and project personnel a consistent point of reference for figuring out how a technology is changing.
Purpose of Technology Readiness Level (TRL)
The purpose of Technology Readiness Levels (TRL) is to measure a system’s maturity of technology components. The measurement allows project personnel to understand how much development a certain technology needs before being utilized. A TRL rating helps in measuring the progress of a project.
Technology Readiness Level (TRL) Scale
TRL is based on a scale from 1 to 9, with 9 being the most mature technology. Using TRLs enables consistent, uniform discussions of technical maturity across different technologies. Decision authorities will consider the recommended TRLs when assessing program risk. [1,2]
|1||Basic principles observed and reported||Lowest level of technology readiness. Scientific research begins to be translated into applied research and development. Examples might include paper studies of a technology’s basic properties.|
|2||Technology concept and/or application formulated.||Invention begins. Once basic principles are observed, practical applications can be invented. Applications are speculative and there may be no proof or detailed analysis to support the assumptions. Examples are limited to analytic studies.|
|3||Analytical and experimental critical function and/or characteristic proof of concept.||Active research and development is initiated. This includes analytical studies and laboratory studies to physically validate analytical predictions of separate elements of the technology. Examples include components that are not yet integrated or representative.|
|4||Component and/or breadboard validation in laboratory environment.||Basic technological components are integrated to establish that they will work together. This is relatively “low fidelity” compared to the eventual system. Examples include the integration of “ad hoc” hardware in the laboratory.|
|5||Component and/or breadboard validation in relevant environment.||The Fidelity of breadboard technology increases significantly. The basic technological components are integrated with reasonably realistic supporting elements so it can be tested in a simulated environment.|
|6||System/subsystem model or prototype demonstration in a relevant environment.||A representative model or prototype system, which is well beyond that of TRL 5, is tested in a relevant environment. Represents a major step up in a technology’s demonstrated readiness.|
|7||System prototype demonstration in an operational environment.||Prototype near, or at, planned operational system. Represents a major step up from TRL 6, requiring the demonstration of an actual system prototype in an operational environment such as an aircraft, vehicle, or space.|
|8||Actual system completed and qualified through test and demonstration.||Technology has been proven to work in its final form and under expected conditions. In almost all cases, this TRL represents the end of true system development. Examples include developmental test and evaluations of the system in its intended weapon system to determine if it meets design specifications.|
|9||Actual system has proven through successful mission operations.||The actual application of the technology in its final form and under mission conditions, such as those encountered in operational test and evaluation. Examples include using the system under operational mission conditions.|
Systems Engineering use of Technology Readiness Level (TRL)
The primary systems engineering objective is to gain sufficient technical knowledge to develop the program’s System Requirements Document (SRD) and to verify that the system solution(s) required technology is sufficiently mature, has a TRL 6 or above, before proceeding into an end-item design or Milestone B. 
The Technology Development Strategy (TDS) will describe how a program plans to mature its CTE before proceeding into Milestone B. After Milestone B, a technology maturation plan/strategy should be part of the Engineering and Manufacturing Development (EMD) Phase Acquisition Strategy for those CTE that requires additional concurrency and technological development to achieve a higher TRL. 
Technology Readiness Assessment of Technology Readiness Levels (TRL)
While a Technology Readiness Assessment (TRA) uses Technology Readiness Levels (TRL) as key metrics for the evaluation of each technology, an assessment is more than just a single number at only single point in time. It is a compilation of lower-level assessments that could span several years, based on the program schedule and complexity of the development.
Evaluations can help gauge the progress of technology development, inform program plans, and identify potential concerns for decision-makers throughout acquisitions. Conducting TRAs periodically and during the earlier phases of development can identify potential concerns before risks are carried into the later and more expensive stages of system development.
TRAs can also facilitate communication between technology developers, program managers, and acquisition officials throughout development and at key decision points by providing a common language for discussing technology readiness and related technical risks. Finally, TRA results can inform other assessments and planning activities, such as cost and schedule estimates, risk assessments, and technology maturation plans. 
Technology Readiness Assessment Deskbook
The Technology Readiness Assessment Deskbook – Appendix C, is the best source of TRL information. It covers:
1. Overview of TRL
2. Assessing Hardware Critical Technology Elements (CTE)
3. Assessing Software Critical Technology Elements (CTE)
Technology Readiness Assessment Calculator
The US Air Force developed the technology readiness assessment calculator to assist in the process of determining appropriate technology readiness levels (TRL). This calculator provides a technology maturity assessment at a particular time in development.
Calculator: Technology Readiness Assessment Calculator
Instructions: Technology Readiness Assessment Instructions
Top 6 Lessons Learned in Assessing Technology Readiness Levels (TRL)
- Set the project’s quality standards and goals in a clear way: This means setting clear, measurable quality goals and laying out the steps and standards for figuring out if those goals have been met. Include all important people in the process of managing quality. This includes project team members, customers, and anyone else who has a stake in the project’s success.
- Learn what the TRL (technology readiness level) assessment is for: The TRL assessment is a tool for figuring out how far along a technology or project is. It is used to figure out how likely a project is to succeed and to find any risks or problems that might need to be fixed.
- Find the right TRL scale: There are different TRL scales, each with its own set of criteria and definitions, that can be used. It’s important to pick the right size for your project and know how it’s put together.
- Define the scope of the assessment: The scope of the TRL assessment should be clear so that all relevant parts of the project are included. This could involve technical, financial, legal, and other factors.
- Collect and look at data: To accurately figure out a project’s TRL, it’s important to collect and look at a lot of data. This could include technical data, market data, financial data, and other useful information.
- Communicate results of the assessment: The results of the TRL assessment should be made clear to everyone who needs to know. This could include members of the project team, investors, regulators, and other people who are interested. It is important to be open about the results of the assessment and to point out any areas of concern or risk that may need to be fixed.
Difference Between Technology Readiness Level (TRL) and Manufacturing Readiness Level (MRL)
The difference between Technology Readiness Level (TRL) and Manufacturing Readiness Levels (MRL) is:
- Manufacturing Readiness Levels (MRL): are used to assess the maturity of a given technology, system, subsystem, or component from a manufacturing perspective.
- Technology Readiness Level (TRL): are used to assess the maturity of individual technology.
Manufacturing readiness and technology readiness go hand-in-hand. In conjunction with Technology Readiness Levels (TRL), MRLs are key measures that define risk when technology or process is matured and transitioned to a system. It is common for manufacturing readiness to be paced by technology readiness or design stability. Manufacturing processes will not be able to mature until the product technology and product design are stable.
- There’re different definitions of Technology Readiness Levels, so make sure you follow the one specific to your program or R&D project.
AcqLinks and References:
-  Defense Acquisition Guidebook (DAG) – Chapter 10
-  Technology Readiness Assessment Deskbook – Appendix C
-  GAO Technology Readiness Assessment Guide – Aug 2016
- GAO Technology Readiness Assessment Guide – Jan 2020
- Technology Readiness Assessment Calculator
- Technology Readiness Assessment Instructions
- TRL Cheat Sheet