Software Project Estimation

Project estimation is the practice of predicting how much time, effort, and cost a software project will need before it is built. Accurate estimation helps teams plan realistic schedules and budgets. Different methods suit different situations, from traditional models to Agile-style estimation.

Function Point Analysis

Function Point Analysis measures the size of a software project based on what it actually does for the user, rather than how many lines of code it takes to build it. Function Point Analysis (FPA) measures system complexity from user-facing inputs and outputs, independent of programming language.

It works well when you have solid requirements but no KLOC estimate yet. This makes it useful early on, before a team has even decided which programming language or technology they will use. 

COCOMO Model

COCOMO (Constructive Cost Model), estimates how much effort, time, and team size a software project will need based on its size and a set of project-specific factors. Function points measure the functionality delivered to users rather than the LOC, providing an alternative way to estimate project size.

COCOMO actually works well together with Function Point Analysis, since FPA can supply the size estimate that COCOMO then uses to calculate cost and schedule.

Story Points in Agile

Story Points are standard in Agile environments. Teams rate user stories by relative complexity, then track velocity to project progress. They are fast and team-specific, but do not produce the total-cost baseline that procurement and long-range planning require.

Instead of trying to predict exact hours or cost, story points just compare how big one task feels relative to another, which fits much better with Agile's iterative, ever-changing nature.