Estimating Time Effectively

When working on a project, or proposing work for a client, it can sometimes be difficult to estimate the time needed to undertake the activities to the required standard and budget. This can be particularly tricky for people who are new to project management.

To an extent, estimating time is something which becomes easier with practice. The more you do an activity, the more likely you are to be able to accurately estimate the time it will take for you to complete it. However, if time is estimated incorrectly, projects are at risk of going off course, going over budget and missing the deadline.

To help you estimate time effectively, there are some basic steps you can take.

Firstly, you should identify all the tasks that need to be done to achieve the project goals. By breaking down a project into its component parts, the full extent of the work can be seen.

For example, stating ‘produce a report’ is insufficient because the report may first require research and multiple drafts. Therefore, it is best to be as specific as possible e.g. (1) conduct desk-based research into XYZ, (2) write a 5,000-word report into XYZ. You should then use reason and common sense to work out how long each of these separate tasks is likely to take.

Secondly, if others are involved in the delivery of the project, you should assign specific tasks to individuals and ask them, from their own experience, how long they estimate the task will take. If you are still unsure, it is worth asking someone who has done similar work in the past for their advice.

Some project managers use time estimation formulae to assist them in producing time estimates. The Project Evaluation and Review Technique (PERT) formula involves the following:

(Most Optimistic Prediction + (4x Most Likely Prediction) + Most Pessimistic Prediction) divided by 6

If the estimate needs to be cautious (for example in a high-risk project), then it is best to err on the pessimistic prediction. The formula, can be amended to the following:

(Most Optimistic Prediction + (3x Most Likely Prediction) + (x2 Most Pessimistic Prediction)) divided by 6

Once you can estimate the timings of the activities in your project, you will be in a stronger position to determine deadlines, costings and the resources needed to complete the task. It will also help you prioritise work, especially if some tasks are dependent on the completion of others. Your calculations may assist you in completing other project management tools such as Gantt charts.

About the author

Nathan is a member of the senior management team at RWA and manages the company’s e-learning, content and professional standards department. He joined RWA as a content writer in 2016, on successfully completing his PhD. Nathan previously worked in the private, public and charitable sectors and has a broad range of experience, including research and analysis, project delivery, corporate governance, and team leadership.

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