Effort Estimation

Types

1. Parametric Technique(Mathematical parameters based techniques)
   • Productivity based : effort estimation through pre-base-lined productivity or project delivery rate derived on past data
   • COCOMO : Effort estimation through Constructive Cost Model regression equation derived on past data
2. Heuristic(Experience and Discussion based technique)
   • Work Breakdown Structure(Bottom Up) : Effort estimation through requirements decomposition into granular work packages and summing up the effort
   • Expert Judgement : Effort estimation based on expert experience and agreement
   • Monte Carlo Simulation : Effort estimation through statistical model requiring considerable amount of data
   • Estimation by Analogy : Effort estimation by experienced professionals based on similar projects executed in the past

Example formula to calculate effort using COCOMO and PERT

For development/testing projects COCOMO uses :

Total Schedule(in months) = $ y * \sqrt{PY}$

PY is number of Person Years
Value of Y is : - 2.5 - 3 for <= 180 person months - 2 - 2.5 for > 180 person months

PERT Schedule Estimation formula is :

Schedule = $(O+4M+P)/6$

where, O = Optimistic Schedule
M = Most Likely Schedule P = Pessimistic Schedule