ISO 14253-2:2011给出了“测量不确定度估算指南”（简写为GUM）概念的实施指南，该指南将应用于GPS领域（测量）标准和测量设备的校准以及工件GPS特性的测量。其目的是促进关于如何实现不确定度声明的完整信息，并为测量结果及其不确定度（买方和供应商之间的关系）的国际比较提供基础。 ISO 14253-2:2011旨在支持ISO 14253-1。在解释GPS规范时，这两部分都有利于公司的所有技术功能[i。 e、 工件特性公差和测量设备计量特性的最大允许误差（MPE）值]。 ISO 14253-2:2011介绍了不确定度管理程序（PUMA），这是一种基于GUM的实用迭代程序，用于在不改变GUM基本概念的情况下估算测量不确定度。它一般用于估算测量不确定度，并给出以下不确定度声明:单次测量结果；两个或多个测量结果的比较；将一个或多个工件或测量设备的测量结果与给定规格进行比较[i。 e、 测量仪器或测量标准的计量特性的最大允许误差（MPE），以及工件特性的公差极限等]，用于证明符合或不符合规范。 迭代法基本上基于上限策略，即高估所有级别的不确定性，但迭代控制高估量。故意高估而非低估，对于防止基于测量结果的错误决策是必要的。高估的数量由对形势的经济评估控制。 迭代法是公司计量活动中实现利润最大化和成本最小化的工具。迭代法/程序在经济上是自我调整的，也是改变/减少测量中现有不确定度的工具，目的是降低计量（制造）成本。迭代法使得在不确定性估计和预算中在风险、努力和成本之间达成妥协成为可能。

ISO 14253-2:2011 gives guidance on the implementation of the concept of the "Guide to the estimation of uncertainty in measurement" (in short GUM) to be applied in industry for the calibration of (measurement) standards and measuring equipment in the field of GPS and the measurement of workpiece GPS characteristics. The aim is to promote full information on how to achieve uncertainty statements and provide the basis for international comparison of measurement results and their uncertainties (relationship between purchaser and supplier). ISO 14253-2:2011 is intended to support ISO 14253-1. Both parts are beneficial to all technical functions in a company in the interpretation of GPS specifications [i.e. tolerances of workpiece characteristics and values of maximum permissible errors (MPEs) for metrological characteristics of measuring equipment]. ISO 14253-2:2011 introduces the Procedure for Uncertainty MAnagement (PUMA), which is a practical, iterative procedure based on the GUM for estimating uncertainty of measurement without changing the basic concepts of the GUM. It is intended to be used generally for estimating uncertainty of measurement and giving statements of uncertainty for: single measurement results; the comparison of two or more measurement results; the comparison of measurement results from one or more workpieces or pieces of measurement equipment with given specifications [i.e. maximum permissible errors (MPEs) for a metrological characteristic of a measurement instrument or measurement standard, and tolerance limits for a workpiece characteristic, etc.], for proving conformance or non-conformance with the specification. The iterative method is based basically on an upper bound strategy, i.e. overestimation of the uncertainty at all levels, but the iterations control the amount of overestimation. Intentional overestimation and not underestimation, is necessary to prevent wrong decisions based on measurement results. The amount of overestimation is controlled by economical evaluation of the situation. The iterative method is a tool to maximize profit and minimize cost in the metrological activities of a company. The iterative method/procedure is economically self-adjusting and is also a tool to change/reduce existing uncertainty in measurement with the aim of reducing cost in metrology (manufacture). The iterative method makes it possible to compromise between risk, effort and cost in uncertainty estimation and budgeting.