Sofware Estimation includes Size,Effort,Schedule and Cost.
Estimation is a per-development activity which bows the first seed and proves to be a real foundation of a successful project delivery. It initiates the the beginning of project planning activities.
Wikipedia says ‘Estimation is the process of finding an estimate, or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable.
We can say that its a raw predictive technique established to ease out the processes followed after it. These options may include
- Estimate the size
- Estimate the effort
- Estimate the schedule
- Estimate the project cost
Estimate the size:
Though it is difficult to measure size in advance, but we may use conditions like best case and worst case scenario to reach an acceptable level of agreement.
There are activities like approximate man-hours, budget/cost, duration, etc. of the project are dependent on the size. For example:
Sizing will help
- To allocate budget
- To get the Manpower requirement
- To get the hardware resource requirement
- To quote the price for the project
- To compare the other project
- To Select the best & valuable project.
Approaches to Estimating size:
Estimate the effort:
Now we have estimated the size and if we know the project team/programmer productivity then we can provide an estimate of efforts.
For example: Effort estimation= estimated size × productivity
Estimate the schedule:
We know the productivity, efforts /man-hours required to accomplish the tasks in hand. We have to come up with a schedule to allocate resources as per the task and also attach a timeline with each one of it. All this can be estimated if we have all the prior information in hand.
We can use past experience or popular scheduling methods like COCOMO II. As we follow SDLC so we just have to organize total duration given time into the lifecycle-phases.
For example: Work Breakdown Structure (WBS)
Estimate the project cost:
The cost of developing the software is deduced by multiplying the estimated effort to rate per hour for each resources.
For example: Cost estimation= estimated effort × rate per hour × no. of resources + overheads.
Through the sizing and costing methods discussed above,A fairly acceptable estimation could be achieved but as they, “No size estimation method is foolproof or particularly accurate”.