REG NASA-LLIS-1772-2006 Lessons Learned - Know How Your Software Measurement Data Will Be Used.pdf

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1、Lessons Learned Entry: 1772Lesson Info:a71 Lesson Number: 1772a71 Lesson Date: 2006-12-8a71 Submitting Organization: JPLa71 Submitted by: David Oberhettingera71 POC Name: Sherry Stukes, Jairus Hihna71 POC Email: Sherry.A.Stukesjpl.nasa.gova71 POC Phone: 818-393-7517 (Sherry Stukes)Subject: Know How

2、Your Software Measurement Data Will Be Used Abstract: When software measurement data used to support cost estimates is provided to NASA by a project without an understanding of how NASA will apply the data, discrepancies may produce erroneous cost estimates that disrupt the process of project assess

3、ment and approval. Major flight projects should verify how NASA plans to interpret such data and use it in their parametric cost estimating model, and consider duplicating the NASA process using the same or a similar model prior to submission.Description of Driving Event: The life cycle cost of comp

4、lex NASA flight software is difficult to forecast accurately, and erroneous or poorly communicated software development cost estimate data may lead to the unjustified cancellation of spaceflight projects. NASA policy requires each flight project to provide cost estimate support data to the NASA Inde

5、pendent Program Assessment Office (IPAO) prior to each major project milestone (Reference (1). JPL experiences with two recent flight projects point out the risk of cost estimate support data being misinterpreted by the recipient. Prior to Preliminary Mission & Systems Review (PMSR), the Mars Scienc

6、e Laboratory (MSL) flight project submitted a Cost Analysis Data Requirement (CADRe) document to the IPAO that included an estimate of source lines of code (SLOC) and other descriptive measurement data related to the proposed flight software. The IPAO input this data to their parametric cost estimat

7、ing model. The project had provided qualitative parameters that were subject to misinterpretation, and provided Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-physical SLOC counts. These SLOC values were erroneously interpreted as logical SLOC count

8、s, causing the model to produce a cost estimate approximately 50 percent higher than the projects estimate. It proved extremely difficult and time-consuming for the parties to reconcile the simple inconsistency and reach agreement on the correct estimate. Similar confusion in the interpretation of c

9、ost measurement data supplied by JPL for the Juno flight project resulted in IPAO overstating by orders of magnitude the cost of the reused portion of the proposed (15 million SLOC) Ground Data System (GDS) software for the Juno mission. The IPAO cost-estimate did not reflect that the cost of re-int

10、egrating/re-testing inherited code would not be incurred by the Juno project because it had been included in the budget for the overall JPL Multi-Mission Ground System Services (MGSS) infrastructure. Once the Juno GDS SLOC numbers were updated to include only the Juno-specific software modifications

11、, the IPAO and Juno project estimates agreed. References: 1. NASA NPR 7120.5, “NASA Program and Project Management Process and Requirements“ 2. NPD 7120.4, “Program/Project Management“ 3. “NASA Cost Estimating Handbook“, http:/www.ceh.nasa.govLesson(s) Learned: When software measurement data used to

12、 support cost estimates is provided to NASA by a major program or project without an understanding of how NASA will apply the data, discrepancies may produce erroneous cost estimates that disrupt the process of program/project assessment and approval.Recommendation(s): Prior to submitting software c

13、ost estimate support data (such as estimates of total SLOC and software reuse) to NASA for major flight projects (over $500 million), verify how the NASA recipient plans to interpret the data and use it in their parametric cost estimating model. To further preclude misinterpretation of the data, the

14、 software project may wish to duplicate the NASA process using the same or a similar parametric model, and compare the results with NASAs.Evidence of Recurrence Control Effectiveness: JPL will reference this lesson learned as additional rationale and guidance supporting Paragraph 5.9.2.5 (Cost Estim

15、ating) in the Jet Propulsion Laboratory standard “Flight Project Practices, Rev. 6,“ JPL DocID 58032, March 6, 2006.Documents Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Space Operationsa71 Scienc

16、ea71 Exploration SystemsAdditional Key Phrase(s): a71 Program Management.a71 Program Management.Business processesa71 Program Management.Communications between different offices and contractor personnela71 Program Management.Cross Agency coordinationa71 Program Management.Program planning, developme

17、nt, and managementa71 Missions and Systems Requirements Definition.a71 Missions and Systems Requirements Definition.Configuration control and data managementa71 Missions and Systems Requirements Definition.Requirements critical to costing and cost credibilitya71 Systems Engineering and Analysis.a71

18、Systems Engineering and Analysis.Systems analysis - cost analysisa71 Engineering Design (Phase C/D).a71 Engineering Design (Phase C/D).Software Engineeringa71 Mission Operations and Ground Support Systems.a71 Mission Operations and Ground Support Systems.Mission operations systemsa71 Additional Cate

19、gories.a71 Additional Categories.Financial Managementa71 Additional Categories.Flight Operationsa71 Additional Categories.Ground Operationsa71 Additional Categories.Program and Project Managementa71 Additional Categories.SoftwareAdditional Info: a71 Project: Mars Science Laboratory & JunoProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2007-02-01a71 Approval Name: ghendersona71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-