Standards, or parts of standards, are not always adopted, and are always subject to change-proposals and review. For example, the metric units and prefixes that preceded the SI, were subject to some episodes of user-resistance and subsequent abrogation or revision over eighty years. The SI itself, declared in 1960 as an evolving system, has had units and prefixes added and abrogated, and the notation for the metrological multiplication operators changed several times. Presumably, change will continue to be required. How can those change-proposals be assessed? A framework of benefit and risk assessment is suggested, extending a recent tool for visualising the risk of user rejection. The suggested framework is applied to a case study ‘syntax for a digital SI’.

标准或部分标准并不总是采用的，并且总是受变更建议和审查的约束。例如，在SI之前的度量单位和前缀在80多年来受到用户抵制和随后的废除或修订的影响。SI本身在1960年被宣布为一个不断发展的系统，已添加并取消了单位和前缀，并且计量乘法运算符的表示法已多次更改。据推测，将继续需要进行更改。如何评估这些变更建议？提出了利益和风险评估框架，扩展了用于可视化用户拒绝风险的最新工具。建议的框架适用于案例研究“数字SI的语法”。