Towards Estimating Schedule for COSYSMO:�A Workshop

2023 BCSSE & PSM Forum

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Boehm COCOMO Forum

Aerospace@Chantilly & Online

November 15, 2023 at 14:25 Eastern

Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Agenda

The Problem

• Background
• Comparison to Software Projects
• What We Have: Valerdi & Wheaton provide hints
• Jim tries an analysis

Workshop proper

• Jim states issues

Appendix

Bibliography

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Background: There’s No Schedule Estimation Model

• COSYSMO (”COSYSMO 1.0”) was developed by Ricardo Valerdi in 2005 [1]. It is a cost model for systems engineering projects.
• The most recent model is my COSYSMO 3.0 [2]; it includes the features of previously published models.
• Neither of these (nor any other full COSYSMO model) includes a schedule estimation model.
• But one would be useful.

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Comparison to Software Projects

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Valerdi & Wheaton’s “Staffing Profile Chart”

• [3] includes this “staffing profile chart” as its Figure 2 “Systems Engineering Effort Profile”:

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• The horizontal axis must be time, divided into Life Cycle Process phases
• The chart therefore may be interpreted as providing duration information

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Analysis of Staffing Profile Chart

• Two kinds of information displayed in the chart may perhaps be interpreted to provide duration information:
• The width of each of the four ISO/IEC 15288 phases (duration information);
• The shapes (height = staffing level, vs time) of each phase for each ANSI/EIA 632 fundamental process (staffing level over time information)
• Unfortunately, the paper doesn’t explain how this potential duration information was determined
• Perhaps some organization’s view of a “standard” systems engineering project?
• Based on project experience?
• At best, the chart by itself would only provide relative information (e.g., relative staffing levels)

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

An Important Caveat

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• The scope of this schedule model is “system engineering”
• Not “the whole project”

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Jim’s Notional Schedule Diagram

• System Engineering effort for new development is expended in a mostly bimodal distribution, where during a Consult phase system engineers merely support other disciplines.

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Conceptualize; Develop

Operational Test & Evaluation; Transition to Operation

Consult

Time

Headcount

Example issues:

• What duration is needed for Conceptualize + Develop? For OT&E + Transition? (These can be absolute, or %ages.) Alternatively, what average headcount?
• How should effort be divided among the three phases?
• What headcount is needed for Consulting? Zero?

Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Jim’s Notional Schedule Diagram (Expanded)

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Issues toward Determining a Schedule Estimator for Systems Engineering

• Is there better information in the literature?
• How can the Staffing Profile Chart be used to make a schedule estimator (partial or full)?
• Is Jim’s concept of a Consult phase useful?
• Could we get companies to provide us schedule information on projects?
• With effort information

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Appendix: More from [3]

• This is extracted from Table 5 of [3]. Each row describes how the effort of that Fundamental Process is distributed across the Phases.

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction

Bibliography

1. Valerdi, R. The Constructive Systems Engineering Cost Model. Los Angeles, CA: University of Southern California, 2005.
2. Alstad, J.P., “Development of COSYSMO 3.0: An Extended, Unified Cost Estimating Model for Systems Engineering”, Procedia Computer Science 2019, pp 55-62.
3. R.Valerdi, M.Wheaton, “ANSI/EIA632 As a Standard WBS for COSYSMO,” AIAA 1st Infotech@Aerospace Conference, Arlington, VA, September 2005.
4. B. Boehm, et al, Software Cost Estimating with COCOMO®️ II, Prentice Hall, 2000

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Boehm CSSE

Center for Systems and Software Engineering

ESSE: Introduction