COMMENTARY
testing could fail a system that is providing a valuable capability, because it didn’t meet a lofty requirement. A related risk is that overly ambitious requirements increase the evaluation’s susceptibility to uncon- trolled variables, as the following example from a sensor’s requirements document highlights.
KPP: 99.9 percent probability of detection.
This requirement leaves very little room for the system to fail test iterations and still meet the requirement. This quest for perfection makes the eval- uation more susceptible to uncontrolled variables, such as user error or something that has little to do with the core capa- bility of the system. Tat is, the system might fail a test, but the reason could be a Soldier error or inclement weather.
amount of data required to ensure that the system is meeting the requirement with statistical confidence. Figure 2 demonstrates the impact that ambitious requirements could have on the design of weapon system reliability testing. Te greater the number of rounds needed for an acceptable test, the more costly the test will be, in time and money.
that the system fails to meet its require- ments. Remember: system requirements drive the system design. Materiel develop- ers may consider design factors that they otherwise would not consider in order to support these extra or infrequently used requirements. Tese decisions can result in a suboptimal system design as well as the expenditure of research and development funds to develop the required capability.
Another problem is requiring too high a level of statistical confi- dence. Statistical confidence is a scientific parameter used to make sure the test produces enough data to show that the demonstrated results are representative of the system at any time it is used during its life cycle. A statistical confidence of 80 percent is the Army accepted best- practice standard for an adequate test design. Reducing the statistical confi- dence below 80 percent increases the risk that the demonstrated test results are not representative of the system’s actual performance. Statistical confidence can be reduced below 80 percent in specific scenarios, however, when circumstances or resource constraints require the acqui- sition community to assume more risk.
A big problem with ambitious require- ments is the necessity to increase the
The test and evaluation community has observed five common challenges to well-developed requirements. These enemies of sound requirements have stymied program development and increased the scope of testing.
Ambitious requirements have their place, but it is critical that acquisition stake- holders determine whether the potential benefits are worth the additional risk of failure and the necessary resources. Te requirements development process should include an analysis showing that the ambi- tious level of performance is necessary to complete the mission.
CHALLENGE #3: EXTRA OR INFREQUENTLY USED REQUIREMENTS Extra or infrequently used require- ments also can unnecessarily increase the resources required to support system development and testing, as well as the risk
Te design impacts created by extra or infrequently used requirements can increase program costs in both the development and sustainment phases. Te test and evaluation community must design a test to verify that the system meets such a requirement in the expected combat environment. The risk increases the chance that the system fails because the conditions surrounding the requirement may be difficult to meet. Te example below from an unmanned ground system demonstrates some of these challenges.
KPP: Unmanned system control. The system controller must have the ability to achieve and main-
tain active and/or passive control of any current Army and Marine Corps battalion and below level unmanned (air or ground) system and/or their respective payloads in less than three minutes.
This KPP requires development of a universal controller that operates with all Army and Marine Corps unmanned air and ground systems. Te benefits of a universal controller are obvious: It drives commonality and reduces the number of pieces and parts the unit has to carry and maintain. But the chal- lenges of such a broad requirement are less obvious: It drives a hardware and software solution that is capable of
https://asc.ar my.mil 149
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160 |
Page 161 |
Page 162 |
Page 163 |
Page 164 |
Page 165 |
Page 166 |
Page 167 |
Page 168 |
Page 169 |
Page 170 |
Page 171 |
Page 172 |
Page 173 |
Page 174 |
Page 175 |
Page 176
