Estimation is a management activity which calculate how long a Task would take to complete.
Basically organization adapt only two technique :-
1. People who are expertise on the task to be done.
2. Consulting the resource who will do that task.
People who are expertise on the task to be done. :-In this process , we interact with the individual contributors and experts and based on previous data, we create a work-breakdown structure of project. here you get a basic understanding of effore, duration, dependencies and resource requirements.
This is also known as bottom-up estimation technique.
Consulting the resource who will do that task.:-Although we can estimate with experts but to make it more robust we should also consult with experienced resources.
Our experience has been that successful negotiations about estimates are those where the focus is less on winning and losing and more about figuring out how best to balance competing pressures in the realms of quality, schedule, budget and features.
As per the process & CMM standard adopted by the reputed organizations, there are five effort estimation technique :-
1).Function point :-
2).Delphi Technique :-
3).Use-case technique :-
4).Work Break-down structure :-
5).Three point Estimation :-
Function point :- For each function an approximate weightage will be given.
here we focus on mainly three things : Size, Duration and Cost.
based on no. of function and weightage of each function we perform our estimation :-
|Function Total Points||240|
|Per point defined Estimate||4.5|
|Total men Hours||240*4.5= 1080|
Delphi Technique :-Here experts will come into esitance & For most of our work packages we use the Delphi method. We just ask the experts for each work package for their best guess, normal guess, and worst guess. Thus we obtain three figures for the expected effort: E(optimistic), E(normal), and E(pessimistic), then combine them with this formula
Effort = (E(optimistic)+4*E(normal)+E(pessimistic))/6.
Use-case technique :-A Use case is a relation between user and system, by the knowledge of use-case over all size of project can be estimated easily.
There is a very clear relation between usecase and code, so there is an approach for estimating and planning with use-case.
Use Case Point:-The number of use case points in a project is a function of the following:
the number and complexity of the use cases in the system
the number and complexity of the actors on the system
various non-functional requirements (such as portability, performance, maintainability) that are not written as use cases
the environment in which the project will be developed (such as the language, the team’s motivation, and so on)
Work Break-down structure :-Here we break our project/task in small pieces.
Three point Estimation :- Here we performe our estimation based on statical data.
Based on static data we consider only three things , Best case,Most Likely case &Worst case
and we apply on them double traingle distribution formula :
E = (best case + 4*most likely case + worst case)/6