A standard is an agreed level of quality used as a measure, or norm, in comparative evaluations. It needs to be evaluated on a regular basis through the ongoing work of the metadata manager/taxonomist. Use an industry standard if you can find one that applies and extend it as needed. Such a standard is created by industry members to meet the specific needs of that industry, standards adoption results in huge cost savings. Examples include Dublin Core, ONIX, SMPTE, PRISM, (PRISM DIM2), METS, MODS, XMP, MARC, IPTC, GILS, SCORM, IMS, JDF. Which one(s) you use depends on the business purpose(s) you want to accomplish.