• Estimate tasks times
For each task, estimate the effort involved.
If it is a fixed-duration task then also estimate the duration.
If you already understand how to do all the tasks yourself then you can simply run down the list and write down the man-days of effort next to each task.
In reality you probably will not be able to do this for every tasks, so you will need to get help from experts in the area.
Estimates given by the person who is likely to do the work are generally more accurate because they have a good idea of what will be involved.
When asking for someone else’s estimate of a task ensure that they have the correct understanding of the task.
For example, if you want someone to estimate effort for a set of project activities, it is not enough to e-mail a list of activity names and ask that they return the list with numbers added.
In order to give a meaningful estimate, people usually need to know what the starting point of the task will be, what the task deliverables will be, and what the other task interfaces are-in other words, the same information you would need to give if you were allocating the task to someone during the project.
They only information you should not give your estimator is any indication of deadline or timing constraints, because doing so tends to influence the estimate.
When asked to provide an estimate, most people will usually give a number that includes a large safety margin.
Such worst-case estimates protect the estimator because it is then very unlikely that the task will take longer than estimated.
This means that estimates tend to be at the upper end of the range of what people really think is require.
Managers know this and have sometimes cut task estimates before using them, to compensate.
This can weaken the manager’s hand when the times comes to do the works since the person who was asked for the estimate probably feels vindicated rather than guilty if the deadline is missed.