Object-Oriented and Classical Software Engineering Fifth Edition, WCB/McGraw-Hill, 2002 Stephen R. Schach [email protected] 9OverviewPlanning and EstimatingPlanning and the Software ProcessPlanning and the Software Process (contd)Estimating Duration and CostHuman FactorsMetrics for the Size of a ProductLines of CodeLines of Code (contd)Software ScienceMetrics for the Size of a Product (contd)FFP MetricFFP Metric (contd)Function PointsFunction Points (contd)Slide 18Slide 19Analysis of Function PointsMk II function pointsTechniques of Cost EstimationTechniques of Cost Estimation (contd)Slide 24Intermediate COCOMOIntermediate COCOMO (contd)Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36COCOMO IICOCOMO II (contd)Slide 39COCOMO II (contd)Tracking Duration and Cost EstimatesResourcesUse of Resources Varies with TimeWork CategoriesCompletion of Work ProductsWork PackageHow to Plan Software DevelopmentSoftware Project Management Plan (SPMP)Framework for SPMPIEEE SPMPPlanning of TestingPlanning of Object-Oriented ProjectsPlanning of Object-Oriented Projects (contd)Training RequirementsDocumentation StandardsTypes of DocumentationSlide 57CASE Tools for the Planning PhaseTesting during the Planning PhaseSlide 9.1© The McGraw-Hill Companies, 2002Object-Oriented and Classical Software Engineering Fifth Edition, WCB/McGraw-Hill, 2002Stephen R. [email protected] 9.2© The McGraw-Hill Companies, 2002CHAPTER 9PLANNING AND ESTIMATINGSlide 9.3© The McGraw-Hill Companies, 2002OverviewPlanning and the software processEstimating duration and costSoftware project management plan componentsSoftware project management plan frameworkIEEE software project management planPlanning of testingPlanning of object-oriented projectsTraining requirementsDocumentation standardsSlide 9.4© The McGraw-Hill Companies, 2002Planning and EstimatingBefore starting to build software, it is essential to plan the entire development effort in detail Planning continues during development and then maintenance–Initial planning is not enough–The earliest possible detailed planning is after the specification phaseSlide 9.5© The McGraw-Hill Companies, 2002Planning and the Software ProcessAccuracy of estimation increases as the process proceedsSlide 9.6© The McGraw-Hill Companies, 2002Planning and the Software Process (contd)Example–Cost estimate of $1 million during the requirements phase»Likely actual cost is in the range ($0.25M, $4M)–Cost estimate of $1 million in the middle of the specification phase »Likely actual cost is in the range ($0.5M, $2M)–Cost estimate of $1 million end of the specification phase (earliest appropriate time)»Likely actual cost is in the range ($0.67M, $1.5M)This model is old (1976)–Estimating techniques have improved–But the shape of the curve is likely to be similarSlide 9.7© The McGraw-Hill Companies, 2002Estimating Duration and CostAccurate duration estimation is critical Accurate cost estimation is critical–Internal, external costsThere are too many variables for accurate estimate of cost or durationSlide 9.8© The McGraw-Hill Companies, 2002Human FactorsSackman (1968) showed differences of up to 28 to 1 between pairs of programmers He compared matched pairs of programmers–Product size–Product execution time–Development time–Coding time–Debugging timeCritical staff members may resign during projectSlide 9.9© The McGraw-Hill Companies, 2002Metrics for the Size of a ProductLines of Code (LOC) Software ScienceFFPFunction PointsCOCOMOSlide 9.10© The McGraw-Hill Companies, 2002Lines of CodeLines of code (LOC), orThousand delivered source instructions (KDSI) –Source code is only a small part of total software effort –Different languages different lengths of code –LOC not defined for nonprocedural languages (like LISP) –It is not clear how to count lines of code»Executable lines of code?»Data definitions ? »Comments? »JCL statements? »Changed/deleted lines? –Not everything written is delivered to the clientSlide 9.11© The McGraw-Hill Companies, 2002Lines of Code (contd)LOC is known when the product finishedEstimation based on LOC is doubly dangerous –To start estimation process, LOC in finished product must be estimated–LOC estimate is then used to estimate the cost of the product — uncertain input to an uncertain cost estimatorSlide 9.12© The McGraw-Hill Companies, 2002Software ScienceMetrics based on number of operands, operatorsLimited predictive power—metrics can be computed only after the product has been implementedThere are major doubts about the validity of Software ScienceSlide 9.13© The McGraw-Hill Companies, 2002Metrics for the Size of a Product (contd)Metrics based on measurable quantities that can be determined early in software life cycle –FFP–Function PointsSlide 9.14© The McGraw-Hill Companies, 2002FFP MetricFor cost estimation of medium-scale DP systemsThe three basic structural elements of DP systems–files, flows, and processes Given number of files (Fi), flows (Fl), processes (Pr)–Size (S), cost (C) given by S = Fi + Fl + Pr C = b  SConstant b varies from organization to organizationSlide 9.15© The McGraw-Hill Companies, 2002FFP Metric (contd)Validity and reliability of FFP metric were demonstrated using a purposive sample –BUT, the metric was never extended to include databasesSlide 9.16© The McGraw-Hill Companies, 2002Function PointsBased on number of inputs (Inp), outputs (Out), inquiries (Inq), master files (Maf), interfaces (Inf) For any product, size in “function points” is given byFP = 4  Inp + 5  Out + 4  Inq + 10  Maf + 7  InfOversimplification of a 3-step process.Slide 9.17© The McGraw-Hill Companies, 2002Function Points (contd)1. Classify each component of product (Inp, Out, Inq, Maf, Inf) as simple, average, or complex. –Assign appropriate number of function points–Sum gives UFP (unadjusted function points)Slide 9.18© The McGraw-Hill Companies, 2002Function Points (contd)2. Compute technical complexity factor (TCF) –Assign value from 0 (“not present”) to 5 (“strong influence throughout”) to each of 14 factors such as transaction rates, portability–Add 14 numbers  total degree of influence (DI)TCF = 0.65 + 0.01  DI–Technical complexity factor (TCF) lies