project estimation

Project Estimation

For an effective management accurate estimation of various measures is a must. With correct estimation managers can manage and control the project more efficiently and effectively.

Project estimation may involve the following:

  • Software size estimation
    • Software size may be estimated either in terms of KLOC (Kilo Line of Code) or by calculating number of function points in the software. Lines of code depend upon coding practices and Function points vary according to the user or software requirement.
  • Effort estimation
    • The managers estimate efforts in terms of personnel requirement and man-hour required to produce the software. For effort estimation software size should be known. This can either be derived by managers’ experience, organization’s historical data or software size can be converted into efforts by using some standard formulae.
  • Time estimation
    • Once size and efforts are estimated, the time required to produce the software can be estimated. Efforts required is segregated into sub categories as per the requirement specifications and interdependency of various components of software. Software tasks are divided into smaller tasks, activities or events by Work Breakthrough Structure (WBS). The tasks are scheduled on day-to-day basis or in calendar months.
    • The sum of time required to complete all tasks in hours or days is the total time invested to complete the project.
  • Cost estimation
    • This might be considered as the most difficult of all because it depends on more elements than any of the previous ones. For estimating project cost, it is required to consider –
      • Size of software
      • Software quality
      • Hardware
      • Additional software or tools, licenses etc.
      • Skilled personnel with task-specific skills
      • Travel involved
      • Communication
      • Training and support

Project Estimation Techniques

Project manager can estimate the listed factors using two broadly recognized techniques –

Decomposition Technique

  • This technique assumes the software as a product of various compositions.
  • There are two main models –
    • Line of Code Estimation is done on behalf of number of line of codes in the software product.
    • Function Points Estimation is done on behalf of number of function points in the software product.

Empirical Estimation Technique

  • This technique uses empirically derived formulae to make estimation.These formulae are based on LOC or FPs.
  • Putnam Model
    • This model is made by Lawrence H. Putnam, which is based on Norden’s frequency distribution (Rayleigh curve). Putnam model maps time and efforts required with software size.
    • COCOMO stands for COnstructive COst MOdel, developed by Barry W. Boehm. It divides the software product into three categories of software: organic, semi-detached and embedded.







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