A novel system by which Translation Memory (TM) tools can be evaluated would be desirable for translation industry stakeholders. Such evaluation systems are commonly known as metrics. While metrics devised to evaluate Machine Translation (MT) are well developed, there has been limited work on the creation of a TM tool metric. This paper discusses the creation of a ‘Neo-Metric’ designed to help translators, translation professionals and translation industry stakeholders as they evaluate TM software. Having identified a need for such a metric, a brief literature review is conducted. Variables to be included in the Neo-Metric are discussed, and an initial metric is introduced. This first version of the metric is briefly tested, weaknesses are identified, and based on these initial tests, a refined metric is developed for more in-depth testing along with testing in the field, both to be discussed in future papers.