QSM Associates, Inc. 1 Michael C. Mah Managing Partner QSM Associates, Inc. 75 South Church Street Pittsfield, MA Fax “Why Size Matters” Web Site: NYCity SPIN Presentiation New York NY, May 2003

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5 “If you underestimate the size of your next project, common sense says that it doesn’t matter which methodology you use, what tools you buy, or even what programmers you assign to the job.” Ed Yourdon on “Sizing”..

QSM Associates, Inc. 6 Rifkin’s* Criteria: Estimation Processes 1) Commitments have to be based on work [scope] to be performed; therefore, there must be agreement on this 2) Estimates have to be based on a) the work to be performed and b) historical records of performance 3) Commitments must not exceed the capability to perform, or else there is no reason to estimate * Stan Rifkin, Master Systems Inc. (formerly with Carnegie Mellon SEI)

QSM Associates, Inc. 7 Sizing Has a Purpose v Productivity Measurement (Historical View) v Project Estimation (Future View) v Project Risk Tracking (Present View)

QSM Associates, Inc. 8 Software Measurement and Management – 3 Key Areas Project Estimation “In-Flight” Tracking Support Future Commitments Manage Commitment CommitmentAnalyze Performance on Commitment Project History Assess Viable Strategies Monitor Status & Replan Post Project Analysis Make Commitment

QSM Associates, Inc. 9 QSM Productivity Index (PI) ( industry values by application type ) Productivity Index (PI) w/ ±1 Standard Deviation Avionics Business Command and Control Microcode Process Control Real Time Scientific System Telecommunications Information Engineering Real Time

QSM Associates, Inc. 10 Example – Historical and New Project Assessment

QSM Associates, Inc. 11 Early Warning - Tracking Size for “In-Flight” Projects Data are Consistently in the Amber Region Example

QSM Associates, Inc. 12 Cutter Consortium Study on Software Estimation Source: Cutter Consortium, Benchmark Review Vol. 2, No. 8

QSM Associates, Inc. 13 Perceptions of Size Microsoft Industry Leader? Microsoft Brutal Monopolist? Different views aren’t necessarily crazy None of us has sole possession of the truth Not always Right/Wrong, more often a case of Right/Right Function Points are a Savior Function Points are Evil Counting Code is Relevant Counting Code is Stupid

QSM Associates, Inc. 14 Ed Yourdon on “Sizing”.. “Studies by the Carnegie Mellon SEI indicate that the most common failing of Level 1 (Ad-hoc) software organizations is an inability to make size estimates accurately.”

QSM Associates, Inc. 15 The Common Obstacle to Software Sizing “Never been asked to consider size up front or after the fact; always equated size to effort i.e. number of hours”

QSM Associates, Inc. 16 Software Sizing How do we Describe the Volume of Software?

QSM Associates, Inc. 17 Many Functional Metrics Can be Used to Represent S/W Size v Subsystems v Entities v Function points v Modules v Objects v Programs v SLOC v Actions/Instructions/Statements

QSM Associates, Inc. 18 Functional Metrics (Proxies) v They all represent what has to be created, but at different levels of abstraction v They all can be useful v Knowing the scaling relationships, enables us to use them effectively

QSM Associates, Inc. 19 Size – Scaling Relationships v Objects 150 – 250 loc/Object v Function Points v Modules v Programs v Subsystems 4, ,000 Can Be Determined from Data Typical Examples

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QSM Associates, Inc. 21 For Additional Information Contact: Michael Mah Managing Partner QSM Associates Inc. Clocktower Building 75 So. Church St., Suite 600 Pittsfield, MA Web url: