Project Planning, Estimation and Time Allocation
Project Plans and Project Estimates Adjust for Time and Productivity
Dec 23, 2008
Understanding project time allocation and productivity and using that knowledge is essential to realistic project planning and creating a project schedule that has the best chance of project success. Factoring in real world time allocation is about making adjustments to project estimating to include interruptions to work, personal productivity and natural delays.
Project Estimation Revisited
Project Planning and Estimation showed how to produce better project estimates, but there is an assumption there that needs to be understood. That assumption is 100% time allocation or working on the project task completely and without interruption. In some cases that assumption will be fine but if that is not true then project estimation needs to be revisited. [Project Managers will already factor into schedules the differences between effort, duration and elapsed time.]
Project Time Allocation is Rarely at 100%
Time allocated for a project task typically assumes 100% time allocation and 100% productivity. The key reasons why time allocation may not be at 100% include:
- Interruptions to work from other project team members or externally
- Unproductive project meetings that are attended but do not help to complete tasks
- Natural delays such as social interactions with colleagues, coffee breaks and lunches
- Waiting for others to provide necessary inputs
- Helping other team members to complete their tasks but delaying own task completion
- Other distractions such as company meetings or interaction with line manager
- Multi-tasking on too many project tasks that delays all of them
- Matrix environment that provides time-splicing of resource such as individuals with 50% time allocation on project A and 50% on project B. This reduces productivity due to switching between tasks, which is a form of interruption
Account for Expected Level of Productivity
When the time allocation is lower than expected the level of productivity is also lower than expected. There are a number of ways to account for lower levels productivity and build those into the project planning and project schedule. Two common ways:
- Add an arbitrary “fudge factor” to increase the time allocation for example adding another week to the project schedule. This approach does not consider individual tasks but applies an adjustment as a best guess
- Assume productivity level of say 80% for example a task that is estimated at 5 days of effort will take 6.25 days of effort instead. This approach considers each individual task and each one is adjusted as needed
Different Expertise Level
Beyond time allocation itself there is also the factor of level of expertise. Different people may have different levels of expertise and be expected to complete the same task with different levels of effort and consequently how long it will take. Therefore, estimates are best produced by the people doing the work as they will be the most likely to produce the most accurate project estimates for their work.
Different Productivity with Same Expertise Level
In addition, even two experienced people may have different levels of personal productivity. For example Frederick Brooks in The Mythical Man-Month quoted studies of programmers by Sackman, Erikson and Grant that found: “…ratios between best and worst performances averaged about 10:1 on productivity measures…”. Again, leading to the conclusion that individuals should produce their own project estimates.
Project Planning
Using good project estimates is vital to project planning. Those estimates should preferably be:
- Produced by people doing the work and adjusted as needed for their over-optimism
- Include all project tasks including documentation
- Adjusted if needed for individual time allocation and productivity
Doing this will lead to the most realistic project schedule and so increases the chance of a successful project.
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