Bottom-Up Estimating Definition, Example, Pros & Cons

bottom up estimating

Get access to FREE Trial and explore different features and functionalities of the software. The collaborative approach taken by the bottom-up is one of the many reasons it is efficient, reduces risks, and improves the cost estimating outcome. When you connected with the person who got it done recently, they told you the project cost them around $3000. In the previous step, we mentioned that if you need to prepare a bill of materials, you should mention that in the scope. At this point, you will need to say the person in charge of creating the BoM and the total time it will take to complete this.

What does TAM mean in sales?

Total Addressable Market (TAM) – represents revenue opportunity at 100% market share, as if no competition exists. Serviceable Available Market (SAM) – represents the portion of the TAM that can be served by a company's products and services.

There are opportunities to pull details from related projects from the past. But the point of bottom-up estimation is to create a forecast based on the individual components of this particular assignment. Bottom-up estimating can be a very accurate method to determine the definitive estimate of a project.

Top-Down vs. Bottom-Up Techniques

Projects can be overwhelming, especially if they are long and complex. Say you have taken up a vast construction contract that involves plumbing, tiling, civil work, as well as laying the bricks (basically an end-to-end project). As part of this process, you can encourage everyone on the team to ask questions and express their concerns. If someone has an idea for improving the approach, or a concern about how you’re doing something wrong, they should be encouraged to speak up!

  • These are all top-down tasks that can be assigned to a project team to implement.
  • Since these risks are different, the strategies to manage them are also different.
  • Remember that bottom-up budgeting and cost estimation play an essential role in coming up with the best project budget and a realistic time frame for project completion.
  • This information can be gleaned from past projects, similar projects, or expert opinion.
  • This is called bottom up estimating and results in the overall project cost.
  • The cost and duration estimate for deliverables are determined before the deliverables are divided into the work packages and activities.

The bottom-up approach is systematic and detailed, making it a good choice for projects with many variables. 1 week TOTAL $243, weeks After completing bottom-up estimating, two things are clear for Lance and his team. Luckily, this is something that could be reused in the future, reducing the amount of time involved. Second, this process produced a more accurate estimate, which turned out to be more favorable. If he used bottom-up estimating, the difference would have only been $3,000 and 2 weeks and would have caused the project to be under budget and ahead of schedule. The last thing for Lance’s transition to bottom-up estimating is to provide an example to his team to show its effectiveness. He takes one of his recent projects, a 1500-square-foot house with two bedrooms and two bathrooms.

Bottom-up estimating example

Bottom-up estimating is done to estimate project cost, duration, or resource needs. There is interdependency while calculating these estimates, as duration is directly related to the resources assigned to the work and costs depend on time and resource requirements. As per the PMI methodology bottom-up estimating involves two important processes i.e. creating WBS and defining activities. Alternatively, you can use an analogous estimating technique with the team member. You will look at the actual amount of work that similar tasks required on completed projects.

If you have several projects and tasks to draw information from, you can quickly reach a consensus on how the current task compares to the other tasks. Then you can adjust the estimated work number to show that difference. The team member needs to actively participate in this discussion and in determining the work number that you will use.

Bottom-Up Estimation Vs Analogous Estimation

Project estimation is the process of predicting the most likely amount of resources (time, money, materials, etc.) that will be required to complete a project. It is important because it allows project managers to plan and allocate resources accordingly. Project estimation is not an exact science, and various techniques can be used to estimate a project. Bottom-up estimating is a technique that helps determine the bottom up estimating overall cost and timeline of a project. It works by gathering all the details of a project at the most minute level. It provides a better, more accurate forecast than other project planning methods because it allows managers to see every available element of the project before it even begins. Using the top-down approach, the project timeline and cost accuracy aren’t very precise, as detailed planning hasn’t begun.

bottom up estimating

This may ignore overhead and integration efforts that may occur in addition to the work defined in activities. This is because team members are estimating the piece of work they are responsible for. As they typically have the most knowledge of their work package, their estimates tend to be much more accurate than top-down estimates. The following figure shows the granular estimates for the activities, their aggregation to the work package level and the entire project. Read our detailed articles to learn more about analogous and parametric estimating.

Bottom-up vs Three-point Estimating

A bottom-up analysis also allows managers to implement strategies to help the team execute the project more effectively. A comprehensive bottom-up analysis also allows the manager to identify potential issues before they occur, which allows the team to react more effectively to those that arise. A bottom-up estimate allows the manager to address issues related to the estimates without making significant changes. In practice, bottom-up estimates can be prone to the bias or the interests of the estimators.

bottom up estimating

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