Because an organisation holds ISM at differing confidentiality levels, it identifies the data confidentiality level using FIPS 199 and maps information types with SP 800-60 before choosing techniques. Most ISM support some clear technique but not all have a reliable purge technique; the owner of ISM holding data of moderate sensitivity may accept the risk that clear carries, acknowledging that a well-equipped party might recover some data (IEEE 2883.1 gives further guidance). Purge (or clear, where it applies) can be the better choice over destroy when contractual obligations such as lease returns, environmental concerns, intended reuse inside or outside the organisation, the cost of the ISM or the difficulty of physical destruction apply. The risk decision weighs the consequences of disclosure, the cost and efficacy of recovery, the cost and efficacy of sanitization and how long the data stays sensitive. Decisions follow the decision flow in Figure 1: the confidentiality of the information decides the method, and the media type then decides the technique.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.