Time estimates are a crucial part of project planning. We start with the WBS to be able to plan the activities well. To get any optimization done with these activities such as the sequencing and organizing the activities we have to have time data. The time data to start with are the estimates of the duration of each of the activities. You then arrange the activities with the correct sequence and organization. This is when you are able to make out what activities can overlap others, what intermediate milestone we can plan for etc. Depending on the internal and the external dependencies, you are able to decide when can each of the tasks start and end. This is when you are able to come up with such additional time parameters as the early and late start as well as early and late end times. At this point you would be able to clearly identify the critical path too. The critical path is the longest chain of activities, none of which has any slack/float. This is the path that decides the total duration a project is going to take.

Estimate Accurately

Time duration estimates of all the tasks and sub tasks are important as we have seen. The estimates need to be accurate if we are to come up with an accurate project duration estimate. It is usually easy to estimate the time an activity could take, when you know everything about the task.

In a manufacturing scenario, you usually have accurate estimates of the tasks involved in producing a product. Projects are usually about doing something for the first time. Since your business has been operating in a given domain area you would probably know many things and be able to estimate many of the activities accurately.

Difficulties in Estimation

But, in the project mode there’s always something new to be handled. For example, while you may operate in the building construction business, every building you construct will throw up some new challenges. Accurate estimate for such activities would really have to be a good guess. An educated guess, but a guess all the same. Knowledge based projects and software product development projects offer a huge challenge in estimation. Quite often it is a product you are trying to develop for the first time. Though you and your organization may have dome something similar it was not quite the same. Estimate for something new could vary widely. You may achieve an early breakthrough saving time. On the other hand you may be totally off in estimating the development time.

What then does one do? One practical way to do this is to ask your experienced leaders to bid on estimates. Take couple of the lowest bids and ask for improvement on that. You can try to ask for optimistic and pessimistic estimates and arrive at a statistically valid mean. Another way would be to use some well known models like the COCOMO that simulates the software development processes and come out with an estimate. However, it is so difficult to simulate the development process this model is not used very often.

Time estimates are a crucial part of project planning. We start with the WBS to be able to plan the activities well. To get any optimization done with these activities such as the sequencing and organizing the activities we have to have time data. The time data to start with are the estimates of the duration of each of the activities. You then arrange the activities with the correct sequence and organization. This is when you are able to make out what activities can overlap others, what intermediate milestone we can plan for etc. Depending on the internal and the external dependencies, you are able to decide when can each of the tasks start and end. This is when you are able to come up with such additional time parameters as the early and late start as well as early and late end times. At this point you would be able to clearly identify the critical path too. The critical path is the longest chain of activities, none of which has any slack/float. This is the path that decides the total duration a project is going to take.

Estimate Accurately

Time duration estimates of all the tasks and sub tasks are important as we have seen. The estimates need to be accurate if we are to come up with an accurate project duration estimate. It is usually easy to estimate the time an activity could take, when you know everything about the task.

In a manufacturing scenario, you usually have accurate estimates of the tasks involved in producing a product. Projects are usually about doing something for the first time. Since your business has been operating in a given domain area you would probably know many things and be able to estimate many of the activities accurately.

Difficulties in Estimation

But, in the project mode there’s always something new to be handled. For example, while you may operate in the building construction business, every building you construct will throw up some new challenges. Accurate estimate for such activities would really have to be a good guess. An educated guess, but a guess all the same. Knowledge based projects and software product development projects offer a huge challenge in estimation. Quite often it is a product you are trying to develop for the first time. Though you and your organization may have dome something similar it was not quite the same. Estimate for something new could vary widely. You may achieve an early breakthrough saving time. On the other hand you may be totally off in estimating the development time.

What then does one do? One practical way to do this is to ask your experienced leaders to bid on estimates. Take couple of the lowest bids and ask for improvement on that. You can try to ask for optimistic and pessimistic estimates and arrive at a statistically valid mean. Another way would be to use some well known models like the COCOMO that simulates the software development processes and come out with an estimate. However, it is so difficult to simulate the development process this model is not used very often.

Estimation

August 22, 2009
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Time estimates are a crucial part of project planning. We start with the WBS to be able to plan the activities well. To get any optimization done with these activities such as the sequencing and organizing the activities we have to have time data. The time data to start with are the estimates of the duration of each of the activities. You then arrange the activities with the correct sequence and organization. This is when you are able to make out what activities can overlap others, what intermediate milestone we can plan for etc. Depending on the internal and the external dependencies, you are able to decide when can each of the tasks start and end. This is when you are able to come up with such additional time parameters as the early and late start as well as early and late end times. At this point you would be able to clearly identify the critical path too. The critical path is the longest chain of activities, none of which has any slack/float. This is the path that decides the total duration a project is going to take.

Estimate Accurately

Time duration estimates of all the tasks and sub tasks are important as we have seen. The estimates need to be accurate if we are to come up with an accurate project duration estimate. It is usually easy to estimate the time an activity could take, when you know everything about the task.

In a manufacturing scenario, you usually have accurate estimates of the tasks involved in producing a product. Projects are usually about doing something for the first time. Since your business has been operating in a given domain area you would probably know many things and be able to estimate many of the activities accurately.

Difficulties in Estimation

But, in the project mode there’s always something new to be handled. For example, while you may operate in the building construction business, every building you construct will throw up some new challenges. Accurate estimate for such activities would really have to be a good guess. An educated guess, but a guess all the same. Knowledge based projects and software product development projects offer a huge challenge in estimation. Quite often it is a product you are trying to develop for the first time. Though you and your organization may have dome something similar it was not quite the same. Estimate for something new could vary widely. You may achieve an early breakthrough saving time. On the other hand you may be totally off in estimating the development time.

What then does one do? One practical way to do this is to ask your experienced leaders to bid on estimates. Take couple of the lowest bids and ask for improvement on that. You can try to ask for optimistic and pessimistic estimates and arrive at a statistically valid mean. Another way would be to use some well known models like the COCOMO that simulates the software development processes and come out with an estimate. However, it is so difficult to simulate the development process this model is not used very often.

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