In a performance based environment (as in Performance-Based Agreements), sustainment related specifications, with a specified range of minimum mandatory (threshold) and target (objective) performance capability design parameters are established with accompanying metrics covering the entire enterprise. This includes the system and the supply chain supporting it. Sustained materiel readiness of war fighting capability can then be achieved by developing optimally effective and affordable total ownership costs investment strategies to achieve the sustainment metrics. The metrics should possess the following key attributes. These sustainment metrics are also called Life Cycle Sustainment Outcome Metrics. 
The sustainment metric requirements must reflect user requirements. The metrics and their values should be derived from the systems operational requirements/use (as articulated in the Capabilities-Based Assessment (CBA) process and the planned logistical support strategy to sustain it. They should also be supported by comprehensive and early supportability planning and analyses to balance technology feasibility, Life-Cycle Costs (LCC) and operational needs. 
The sustainment metric requirements must be obtainable. They should also be stated in demonstrable terms reflecting the projected range of military operations (e.g., design reference missions) and intended operating environment that must be supported. These attributes are critical for sustainment requirements to be used within the design tradeoff process along with cost, schedule, and performance. 
The specific metrics should be tailored to the program and its operational and sustainment needs. At a minimum, they should consist of four interrelated metrics: an outcome metric meaningful to the user in achieving and sustaining the operating tempo; a materiel metric to measure the system’s quality; a response metric to measure the quality of the logistics system; and a cost metric. They should be consistently defined within the program and traceable to the operational need. At the top level, the sustainment metrics should focus on providing an effective system that is available and reliable with minimal down time at a reasonable cost. Exact definitions and details can be found in the JCIDS Manual. However, programs have the flexibility to tailor the metrics (including adding additional sustainment metrics (e.g. footprint, manning levels) as long as the intent is met. The following describes the general intent of each of the metrics: 
- Materiel Availability: the percentage of the total inventory (not just the operationally assigned assets) operationally capable at a given time based on materiel condition. This “total inventory” aspect is critical because it not only measures the ability to execute “today’s” missions but also provides an indication of the “surge” ability. Materiel availability is primarily an indication of the percentage of time a system is operationally capable of performing an assigned mission. In addition to the planned missions/scenarios, operating tempo, and sustainment Concept of Operations (CONOPS), this metric is dependent on system reliability and the mean downtime resulting from, but not limited to failures, scheduled downtime, general maintenance or servicing actions.
- Materiel Reliability: the probability the system will perform without failure over a specific interval. This metric focuses on reliability of the entire system and should not be confused with the mission success rate. Defining the criteria for measuring relevant failures (including consistent definitions for failures (e.g., criteria for counting assets as “up” or “down”) and mission critical systems) and clearly defining how time intervals will be measured are important and must be consistent with the other metrics.
- Mean Down Time: the average time an end item is unavailable to perform its assigned mission after it experiences unscheduled or scheduled maintenance actions.
- Ownership Cost: a subset of the total ownership cost, focusing on the operations and support cost. The objective is to use ownership costs to influence program design, acquisition, and sustainment alternative decisions.
The selection of the specific performance metrics should be carefully considered and supported by an operationally-oriented analysis, taking into account technology maturity, fiscal constraints, and the timeframe the capability is required. In implementing Performance-Based Life-Cycle Product Support strategies, the metrics should be appropriate to the scope of product support integrators and providers responsibilities and should be revisited as necessary to ensure they are motivating the desired behaviors across the enterprise. During operations the program can consider measuring additional metrics for configuration control, training effectiveness, overall user satisfaction, etc. The specific metrics selected should tie to existing user performance measures and reporting systems. In addition, existing logistics and financial metrics should be related to these top level user performance metrics and considered as supporting metrics to help provide confidence they can be met as well as identify risk areas. 
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