Cosr risk and risk tool overview
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Cosr risk and risk tool overview Presentation Transcript

  • 1. Jairus Hihn Leigh Rosenberg November 01, 2011 Team X Risk Tool And Team X Cost Risk Tool Overview
  • 2. Methodology
    • Team X focuses on risk identification and initial assessment
      • In the early life cycle it is difficult to crisply distinguish between a risk, an issue, or a concern
      • Items on the Team X Risk List are those items that the team feels are significant enough that the customers’ or reviewers’ attention is required
      • Many of these items can be addressed by adding detail or specificity to the proposal
    • Risk process:
      • Prior to the study the Risk Chair reviews the Team X Risk Checklist and identifies potential risk items
      • Subsystems initiate/revise/reject proposed risks
      • Subsystems score the risk on their subsystem list using the rating scale described in 8.1.2
      • Risk Chair reviews risks and talks to each subsystems engineer to clarify risk descriptions and their scores as needed, enters system level scores (what you primarily see)
      • After the study Risk Chair with key subsystems and the facilitator scrubs risks for consistency in wording and scoring
      • Construct Risk Adjusted Probabilistic Cost Estimate (Also known as S-Curve)
  • 3. Background: Team X RAP Tool
  • 4. Publications
    • “ Identification And Classification Of Common Risks In Space Science Missions”, Jairus Hihn, Debarati Chattopadhyay, Robert Hanna, Daniel Port, Proceedings AIAA Space 2010 Conference and Exposition, 1-3 September, Anaheim, CA.
    • “ Risk Identification and Visualization in a Concurrent Engineering Team Environment”, Jairus Hihn, Debarati Chattopadhyay, Robert Shishko, Proceedings of the ISPA/SCEA 2010 Joint International Conference, June 8-11, 2010, San Diego, CA.
    • “ Risk Mental Models in Concurrent Engineering Teams ” , USC Systems and Software Cost Modeling Workshop, October 2010.
  • 5. Example Risk Checklist: Propulsion
    • Checklist of common risks developed for each subsystem, through review of a subset of prior Team X studies
    • Checklists validated during interviews with Team X subsystem chairs
    • Use of checklists during Team X studies revealed:
        • Lists were useful to Risk chair
        • Subsystem chairs felt the general lists were long, should be tailored to the specific study
        • Would be easier to use if built into tool
  • 6.
    • Translation of impact and likelihood ratings into Red-Yellow-Green for NASA 5x5 risk matrix
    New Risk Scoring Guidance
  • 7. Risk Chair Master Sheet
  • 8. Step 1
    • Risk Chair Goes through Template and identifies likely risks
      • Select copy risk tab
      • Select/import risks from a template or study
      • Both general risk and subsystem risks
    • Risk Chair opens up Study Risks Window
      • Initially blank
      • In end summarizes all risks once populated
  • 9. Example S-Curve from NASA CEH
    • Go back to Add/Edit Tab
    Select Add hit edit to add additional risks not in imported list Select risk and hit edit to revise, add details and score
  • 10. All updates done here
  • 11. Risk-Adjusted Probabilistic Cost Estimate Methodology
      • Estimate/Model Uncertainty
      • Estimated schedule risk based on inputs from Mission Design
      • Technical risks based on key risks based on risks identified by Team X
    Risk-Adjusted Probabilistic Cost Estimate Convolve Yields
  • 12. Risk-Adjusted Probabilistic Cost Estimate Methodology
    • Each WBS level 2 item has its own distributional CER
    • Each WBS line item has an underlying algorithm such as
    • Where model error is captured through a normal distribution on the standard errors of the algorithm ’s coefficients (the β s) and input uncertainty is captured by ranges on the inputs.
    • A Monte Carlo is run on these coefficients and variables
    • Each WBS ’s distribution is then convolved using full correlation in a Monte Carlo run to produce a single total cost distribution
    • This provides a CDF that represents the model and cost driver uncertainty
  • 13. Risk-Adjusted Probabilistic Cost Estimate Methodology Schedule Risk
      • Schedule Schedule distribution is derived from analysis and historical data
      • Likelihood of slip is based on analysis of 19 historical JPL in-house and contracted missions
      • Impact is based on Team X effort profiles and mission design determination of months between launch opportunities
      • Launch opportunities identifed by Mission Design
  • 14. Risk Idenitification and Scoring
    • EHM Flyby is a relatively low risk mission compared to other similar space science missions
      • SC has relatively high heritage
      • Moderate number of instruments
    • There is one significant risks that need to be addressed
      • ASRG performance and delivery date of flight ready is still highly uncertain
      • Specific mitigations are not identified but the impact is based on a best estimate for the cost impact should the risk manifest.
    Implementation Risks R:1 R:2
  • 15. Example EHM Orbiter
    • Estimate uses parametric cost model based on the Team X 50 th -percentile estimate
    • Cost risk analysis indicates that proposed mission has a high likelihood of success
      • Estimated cost with reserves is 70% to 76%.. Typical NASA goal is 70%.
      • Identified risks consumes less than 1/3 rd of planned reserves leaving sufficient reserves to cover ‘unknown-unknowns’
      • The 50 th percentile team X estimate becomes 36% when the identified risks are taken into account
    Risk-Adjusted Probabilistic Cost Distribution (S-Curve)