Developing a schedule for a project can be challenging. You need to estimate two different times in order to schedule the project.
- The time to do the task
- The elapsed time to complete the task
Obviously you need some idea of the time it will take to do a task. These estimates can be tough if you have not done anything like the task before. The best way to develop these estimates is to visualize what you will need to do. Then take your estimate and apply a multiplier for tasks where you are most uncertain of the effort required.
For example, suppose that a task consists of a computer model for a part of the analysis. Computer models often take more time than originally estimated. Suppose you estimate that the model will take 30 hours to develop. In this case, you might want to apply a multiplier of 2x to arrive at a realistic time.
The chart shown below can help you with the selection of a multiplier:
|1.2 – 1.4||You understand how to do the task but you are uncertain of how much data or other detailed analysis will be needed.|
|1.4 – 1.6||You are fairly comfortable with what needs to be done, but there is one element of the task that you are uncertain about.|
|1.6 – 2.0||You have a high level of uncertainty about the task or from past experience you know that you have had problems with similar efforts.|
|2.0 – 3.0||You have never done the task before. The desired outcomes from the task are also uncertain.|