Software Project Planning – I : COCOMO & Putnam

Planning a Software Project

žPlanning is perhaps the most important  activity of management.

  • žThe basic goal of planning is to find the activity which is to be performed for completing  a project.
  • žMoreover, a good plan is that which can handle all the uncertain event which can occur during the development of project.
  • žWe also can say that,  A good planning helps in good decision making.
  • Hence, žLack of planning is a primary cause of schedule slippage, cost overruns, poor quality, and high maintenance costs for software.

 

Some factors to  consider in project planning:

  • žAccuracy required so Cost & Schedule estimation techniques to be used.
  • žLife-cycle model, control functions, and reviews.
  • žLevel of formality in specifications, test plans, etc.
  • Therefore need of organisational structure ( team structure)
  • However, žLevel of verification and validation (independent group?) taken care of.
  • žSo, Planning for management of risk.
  • žAlso, Level of configuration management required.
  • žProject monitoring & controlling techniques and
  • žLevel of quality assurance required.
  • žPersonnel recruitment and training.

Software Cost Estimation

žEstimation of resources, cost and schedule for a software development effort requires experience.

So, žAccess to good historical information and the courage to commit to quantitative measures when qualitative data are all that exist.

žThe importance of software cost estimation is well documented.

Whereas good estimation techniques serve as a basis for communication between software personnel and non-software personnel such as managers, sales people or even customers

žTherefore cost estimation is part of the planning stage of any engineering activity.

žThe difference in cost estimation between software engineering and other disciplines is that in software engineering the primary cost is for people.

However žIn other engineering disciplines, the cost of materials (chips, bricks, or aluminum, depending on the activity) is a major component of the cost that must be estimated.

žTherefore In software engineering, to estimate the cost, we only have to estimate how many engineers are needed.

Uses of Cost Estimation

žSoftware cost estimation has two uses in software project management.

First of all žduring the planning stage, one needs to decide how many engineers are needed for the project and to develop a schedule.

žAnd, In monitoring the project’s progress, one needs to assess whether the project is progressing according to schedule and take corrective action, if necessary.

Basili (1980) described four classes of resources models:

  • žStatic single-variable models
  • žStatic multi-variable models
  • žDynamic multi-variable models and
  • žTheoretical models

žThe static single-variable model takes the form:

Resources = c1* (Estimated Characteristics)C2

where the resources could be effort, project duration, staff size or requisite lines of software documentation. The constants c1 and c2 are derived from data collected from past projects. The basic version of the Constructive Cost Model or COCOMO is an example of a static single-variable model.

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Published by

Gagan Deep

FOUNDER & DIRECTOR, ROZY COMPUTECH SERVICES, KUK, KURUKSHETRA (HARYANA), INDIA I am in the profession of teaching in Computer Science since 1996.  In 1996, established a professional setup “Rozy Computech Services” for providing Computer Education, computer hardware and software services. In this span of 21 years , in conjunction with Rozy’s, I also associated in Teaching with different Institutions like Assistant Professor in University College, Kurukshetra University, Kurukshetra, Guest Faculty in Directorate of Distance Education, Kurukshetra University, Visiting Faculty in University Institute of Engineering & Technology, Kurukshetra University and a Resource person in EDUSAT, Haryana. Besides, I am also serving as Guide and Mentor in various private educational institutions. Also written 7 books on computer science.

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