Top down and bottom up

Top-down and bottom-up estimates are created at different points in a project's life cycle. A top-down estimate takes the whole project and applies an overall timescale and cost. It is created at the beginning of the project and breaks down time and cost across its stages, but it is unlikely to go into further detail because in the early days of the project, no further long-term detail will be available. Despite this, demands to know how long the project will take and how much it will cost will still be made and a response is necessary. Given the high-level nature of a top-down estimate, it is usual to add some contingency to allow for whatever risky assumptions have to be made. An example of a top-down estimate is shown in Figure 7.1.

Figure 7.1 contains expressions of time, cost and quality, but if the project steering group is to approve the plan, it will need something extra to give

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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