Task estimation for a project is a very hard and haunting endeavor, it is even harder when the project is big and complex and consist of a large team. How do you create a project plan and the schedule which is realistic and not based on wishful thinking? How do you avoid project delays and cost overruns which are common in more than 80% of all projects active today? There is nothing more demoralizing than a project which is running late and over budget when you sincerely believe you have done everything humanly possible to make the project finish on time & budget. The good news is there is scientific method to improve your estimates for tasks and therefore for the projects. These methods may be implemented using a task management software or traditionally. Using the following three steps you have a much better chance of completing your projects on time & budget. Task estimation makes a foundation for better planning.
Use Work Breakdown Structure(WBS)
A large project is made up of many complex tasks. It is extremely hard to estimate large and complex tasks correctly. Human nature tends to either underestimate or overestimate work that needs to be done. Each member’s experience and level of expertise plays a significant role in the accuracy of estimations. But using WBS you can get a better result every time regardless of the level of experience of your project members. This makes WBS an important task estimation technique Gather your team in a conference room and list all tasks needed to finish the project. Take each task and break it down to simpler, smaller tasks with the help of your team. The new tasks are called subtasks. Examine each subtask and if it could be broken down into smaller subtasks do so. Keep this process going until your project is made up of only simple and short duration subtasks.
Use 3 point Estimate
For each subtask, ask your team or the person who will be responsible for that task to give you three task estimation techniques for completing the task as shown below:
- B = Best case estimate, The case where all goes well
- W = Worst case estimate, case where all shit that could happen will happen
- M = Most likely estimate, your gut feeling based on past experience
Now use the data for each task in the project and the formula below to calculate the task duration for each task in the project:
Task Duration = (B+ W + (4 * M)) / 6
so as an example if B=4, W=12, and M=6; the task duration is calculated as (4+12 +24)/6=7 (all numbers are rounded to an integer)
Use calculated task duration number for each task in the schedule you make. For each task, ask your team if there are dependencies. Dependency means a task could not be completed if another task is not finished first or a part or service will not arrive on time and so on. Record these dependencies and use them in the activity graph for the project.
Use Activity graph for finding critical path
Activity graph shows several paths a project can take from start to finish working on all tasks you listed in the WBS. A Gantt chart is the best example of an activity graph, any good project management software should have a Gantt chart. I have shown a simple activity graph below and the critical path for it. The critical path is simply the longest past from start to finish. The critical path requires extra attention from you and your team. If there is a need to shorten the project’s duration, the tasks along the critical path are the ones you and your team should pay extra attention to and deal with first.
Using the above tool, your estimates will be much closer to the actual and you and your team will have a much better experience managing and completing projects on time and on budget.
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