独立保证（IA）在行业中用作内部审计和审查，以支持数据和流程的准确性。在公路行业，这是国会众议院疏忽和调查委员会（“布拉尼克委员会”）的一份报告的结果，该报告要求州交通部（DOTs）在涉及联邦资金时进行IA抽样和测试。IA是对所有取样、测试和工艺的无偏见和独立评估。该评估包括评估用于验收公路材料和施工的程序和设备。 23 CFR第637部分要求每个州都有IA计划。IA用于验证取样程序、测试程序和测试设备。IA不同于且不打算作为验收过程或用于验证承包商取样和测试结果。IA与质量控制（QC）不同，也不用于质量控制（QC）目的。如果IA结果表明质量存在潜在问题，则该结果可用于启动附加测试。本标准惯例适用于设计/建造和保修规范以及更传统的承包方法。 作为一项管理原则，IA是DOT的责任，不能委托给承包商。（例如，承包商不得雇佣自己的IA检查员或测试人员。）IA是一个重要工具，有助于确保质量保证（QA）计划的完整性。IA通过评估抽样和测试程序及能力，帮助预防欺诈和其他犯罪活动。IA必须在整个机构内保持一致。（它通过为所有承包商提供公平的竞争环境，让诚实的人保持诚实。 )

Independent Assurance (IA)—Independent assurance is used in industry as an internal audit and review to support the accuracy of data and processes. In the highway industry, it is the outgrowth of a report from the Congressional House Committee on Oversights and Investigations (“Blatnik Committee”) that requires state departments of transportation (DOTs) to perform IA sampling and testing whenever federal funds are involved.Purpose of IA—Independent assurance is an unbiased and independent assessment of all sampling, testing, and workmanship. This assessment includes evaluation of procedures and equipment used for the acceptance of highway materials and construction. 23 CFR Part 637 requires each state to have an IA Program. Independent assurance is used for verification of sampling procedures, testing procedures, and testing equipment.Independent assurance is distinct from, and not intended as an acceptance process or for use in, verification of contractor sampling and testing results. Independent assurance is distinct from, and not intended for, quality control (QC) purposes. If IA results indicate a potential problem with quality, the results may be used to initiate additional testing.Independent assurance sampling shall be done in such a manner as to minimize variability. In order to eliminate material and process variability, split samples should be used. Independent assurance samples may be taken independently of verification or acceptance samples, or may be a split of a verification or an acceptance sample.Deficiencies in acceptance or QC processes that are identified through the IA program must be investigated and resolved. Otherwise, there is no purpose in identifying deficiencies.This standard practice is applicable to design/build and warranty specifications as well as more conventional contracting methods. As a management principle, IA is a responsibility of the DOT that cannot be delegated to the contractor. (For example, contractors shall not hire their own IA inspectors or testers.)Independent assurance is an essential tool that helps to ensure integrity within the quality assurance (QA) program. Independent assurance helps to prevent fraud and other criminal activities by evaluating sampling and testing procedures and competency. Independent assurance must be consistent throughout the agency. (It keeps the honest people honest by providing a “level playing field” for all contractors.)Note—Many of the principles included herein have universal application. Although this standard practice for IA programs is developed specifically for construction materials, it can be applied to other processes. The principles inherent in the use of unbiased, consistent, and reliable information are applicable for any management effort. For example, construction workmanship is frequently inspected by either measurement or examination.