When projects are being started and throughout the life cycle of a project it is normal for the project team to be asked to forecast their effort for the whole project, the next phase or a specific task.
What the project manager is looking for in this forecast is a realistic number of days / hours that the team members require to complete the project, next phase or specific task.
What the team member is looking to do is manage expectations so not to over promise and under deliver while providing a realistic picture of the required effort. As they are responsible and accountable for the estimate they give.
In an ideal world everyone gives a perfect forecast of the required estimate to deliver all parts of the project. As the world is not ideal what can actually happen is that the difference in power in the relationship between the senior person (could be the project manager, project sponsor, resource manager etc) and the project team member results in an inaccurate or unrealistic forecast being provided.
For example, the following situation could occur, a senior manager asking a junior employee to forecast their effort. So the junior employee says they need 50 days to complete the task but this puts the senior manager’s project over budget so the senior manager asks the junior employee to give a “more realistic number” or an “ideal number” so the junior employee gives the forecast the senior manager wants. What may happen next that the junior employee delivers the task close to the original forecast as they were pressured (deliberately or not deliberately) and the senior manager gets annoyed that they are now over budget and may miss the delivery date.
So, who is to blame? Is it the senior manager for (deliberately or not deliberately) pressuring the junior employee to give them a forecast that fitted their budget and timelines? Is it the junior employee for not standing up for themself? Is it the Chief Operations Officer for not having a database of every project ever delivered by the organisation so an objective, and not subjective, approach to project forecasting can be taken?
In my view, all of them are to blame. Project forecasting is not an exact science, but it can be helped if an organisation has a database of the effort taken to deliver all the past projects. This database is then used to objectively forecast the required effort to deliver any project. All organisations can easily and with minimal investment in time, effort and costs create their own database as it is highly likely that organisations do the same or very similar projects over and over again. Even if they do a project that has never been done before the objective data from past projects can be used to help guide the forecast.
In conclusion the balance of power in a project / organisation can negatively influence a project forecast and the expectations of what is possible. But this also creates an opportunity as if the organisation has a database of past projects, they can provide objective and realistic pricing and forecasting of projects, instead of a power imbalance resulting in over promising and under delivering.
Successful International Project Management 