Educational digital resources stored in repositories require metadata in order to describe them properly, and are fundamental for searching and retrieval processes. The aim of this paper is to present an approach for the calculation of metrics that determine the quality level of labeling digital resources, specifically Learning Objects (LOs). We describe how to evaluate resources considering three dimensions such as completeness, consistency and coherence, based on the standard IEEE LOM. In order to validate the results that such metrics exhibit, some experimental tests were performed with synthetic and real OAs, concluding that they allows evaluating