Task duration management is a practice embedded into the Project Management, because it is necessary for a project manager to accurately estimate and pre-plan durations of all tasks included into the project, as they make up the overall project’s timeframe. Prior to delivering a project timeline, you need to carry out task duration estimation that includes certain amount of objective inputs, scientific forecasting, along with a significant portion of subjective judgment. Specifically, duration calculation process is based on the following inputs:
- Expert Judgment – skillful estimators contribute their expertise and opinions to assist the project manager in planning durations of tasks;
- Industrial Norms – durations of certain tasks are predefined by appropriate industrial standards or regulations, which are guaranteed by established quality-driven processes;
- Risks Assessment – durations of some tasks can be seriously affected by external factors, so if the risks seem high enough it can be helpful to prolong influenced tasks to complete them via a risk-mitigated way;
- Availability of resources – every working unit has certain capacity to process workloads, so it is necessary to not overload the resources with excessive assignments (such as competitive tasks);
- Previous experience – available historical data to support estimation and planning;
How to estimate task duration?
There is one simple method based on three inputs: an optimistic estimate of duration (when all concerned factors aid the work maximally auspiciously), a pessimistic estimate (when work goes on a wrong track), and a most likely estimate (the most sober estimate based on probability of negative and positive scenarios). To get a more true representation of task duration you can use the following formula:
(Optimistic estimate) + (Pessimistic estimate) + (Most likely estimate)
This means to get an average from these three estimates. Let’s say you have 14 days for optimistic scenario, 30 days for pessimistic and 19 days for a most likely one. You need to sum them (63 days) and divide by 3 = 21 days. In other words you get 21 days for the most probable (average) duration.
Resource allocation is a process that usually directly affects duration of project tasks, because some activities will take much less time once more resources are assigned to them (because the amount of work will be processed in parallel by smaller portions). Business resources include the following matters:
Task Duration in Project Plan:
Sometimes, the project managers have to establish certain variance on the project to take into account related risks and some unforeseen circumstances that may hamper a project work. Duration variance may refer to the following factors: