How estimation done: Costs are generally estimated with the help of some methods that are found in Time Management idea such as one-point estimating, analogous estimating, parametric estimating and three-point or PERT estimating; besides all of this there is a different kind of estimation named method of estimation.
Bottom-up estimation is involved in the final distribution time of a project where it adds estimation of costs at each activity or work package, turning it up into control units and then finally works on whole project estimate. So the estimated created by following steps:
• Project management software: There is various kind of software that increases calculation speed needed to estimate costs and the calculations included direct, indirect, overhead and fixed cost calculations for many activities.
• Deciding resource cost rates: resources can be various kinds like human resources, vendors, consultants, suppliers, external technicians etc. and the project managers are aware about the involved rate for the resource cost.
• Reserve analysis: It gathers identification of activities with significant risks and resolution of all efforts needs to manage the occurred risks.
• Cost of quality: The quality efforts are divided as Cost of Quality.
In the time working with integration, often it is asked about estimation of interfaces that follows below kind of scenarios:
• In the New implementation of Sap, the project manager has to execute lots of interfaces to join with the previous systems
• In the B2B integration, a lot of new pattern and messages will come
• Movement from one integration broker to another.
When any of the scenarios will come interfaces are estimated by following the steps and the development is shown there:
2. System interactions with supported adapters
5. Testing and fixing
6. Transport and configuration
8. Going live
All of the steps take extra time that will expand the initial time. The 80/20 principle was invented a long ago that states that spend less time to do more work and if more time spends in the beginning of the estimation then the whole process might take longer time to end. To avoid this scenario, it is important to study about the process and understands it properly then starts the work and as there are more variations of the interfaces that look similar then it will be easy to arrange them as per order.
It must keep in mind that performing estimation is not an easy task as there will be many unknown details about development that can be seem unclear before started; so just go through them and make a detailed report.
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