Requirements Development

Key System Attributes (KSA)

A Key System Attribute (KSA) is a system capability considered crucial in support of achieving a balanced solution/approach to a Key Performance Parameter (KPP) or some other key performance attribute deemed necessary by the sponsor. KSAs are listed in the Capability Development Document (CDD) and Capability Production Document (CPD) with threshold and objective values.  They provide decision-makers with an additional level of capability performance characteristics below the KPP level.

Key System Attributes (KSA) Documents

In the Defense Acquisition System, the Capability Development Document (CDD), Capability Production Document (CPD), and listed in the Acquisition Program Baseline (APB) identify the KSA(s) that contribute to the desired operational capability in a threshold and objective format.  Each KSA is supported by an operational analysis considering technology maturity, fiscal constraints, and schedule before determining threshold and objective values.  KSAs must be measurable and testable and support efficient and effective tests and evaluations. Mandatory KSAs are specified in the JCIDS Manual.

See: Manual for the Operation of the JCIDS – Enclosure B, Appendix A

KSA and Key Performance Parameters (KPP) are expressed in terms of parameters that reflect Measures of Performance (MOPs) using a threshold and objective value. The threshold value is the minimum acceptable value considering cost, schedule, and technology. Performance below the threshold value is not operationally effective or suitable. A KSA also has an objective value, the desired operational goal considering cost, schedule, and technology. Performance above the objective value does not justify the additional expense. The difference between the threshold and objective values sets the trade space.

  • Threshold Value: an attribute is the “Minimum Acceptable Level” value considered achievable within the available cost, schedule, and technology at low-to-moderate risk.
  • Objective Value: an attribute is applicable when a “Desired Level” of performance represents a significant increase in operational utility.

All KPPs and KSA’s are validated by the Joint Requirement Oversight Council (JROC). Advances in technology or changes to system goals may result in changes to the KPP and KSA threshold and objective values which will have to be validated by the JROC again.

Mandatory KSA

  • Availability: A measure of the degree to which an item is in an operable state and can be committed at the start of a mission when the mission is called for at an unknown (random) point in time.
  • Reliability: The most common measures of reliability is Mean Time Between Failures (MTBF) or Mean Time Between Maintenance (MTBM).
  • Ownership Cost: See Total Ownership Cost (TOC)

Difference Between a Key Performance Parameter (KPP) and Key System Attribute (KSA)

If an attribute is considered important but not critical to meeting system goals, it can be classified as a Key System Attribute (KSA). A KSA is a system capability considered crucial to achieve a balanced solution/approach to a Key Performance Parameter (KPP) or some other key performance attribute deemed necessary by the sponsor.

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Requirements Development Steps

There is no set standard way to develop requirements, but they are normally developed following the same basic six (6) steps. These requirements development steps don’t change depending on which SE model is used. All models are similar in their approach, but they usually depict the step differently graphically. The main model that is used is the Systems Engineering “Vee” where requirements development is depicted on the left side.

Below is a list of the basic six (6) steps of requirements development.

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Updated: 2/2/2024

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