One of the principle benefits of creating a bottom-up estimate during planning is that the estimate:
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Calculating Realistic Project Timelines
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GettyImages Run projects like clockwork. Have you ever been on a project where the deadline was way too tight? Chances are that tempers were frayed, sponsors were unhappy, and team members were working ridiculous hours. Chances are, too, that this happened because someone underestimated the amount of work needed to complete the project. People often underestimate the amount of time needed to implement projects, particularly when they're not familiar with the work that needs to be done. For instance, they may not take into account unexpected events or urgent, high-priority work; and they may fail to allow for the full complexity of the job. Clearly, this will likely have serious negative consequences further down the line. This is why it's important to estimate time accurately if your project is to be successful. In this article, we explore some of the methods that you can use for making good time estimates. Why Estimate Time Accurately?Accurate time estimation is a crucial skill in project management. Without it, you won't know how long your project will take, and you won't be able to get commitment from the people who need to sign it off. Even more importantly for your career, sponsors often judge whether a project has succeeded or failed depending on whether it has been delivered on time and on budget. To have a chance of being successful as a project manager, you need to be able to negotiate sensible budgets and achievable deadlines. How to Estimate Time AccuratelyUse these steps to make accurate time estimates: Step 1: Understand What's RequiredStart by identifying all of the work that needs to be done within the project. Use tools such as Business Requirements Analysis, Work Breakdown Structures, Gap Analysis, and Drill-Down to do this in sufficient detail. As part of this, make sure that you allow time for meetings, reporting, communications, testing, and other activities that are critical to the project's success. (You can find out more about these activities in our article, Project Management Phases and Processes.) Step 2: Order These ActivitiesNow, list all of the activities you identified in the order in which they need to happen. At this stage, you don't need to add in how long you think activities are going to take. However, you might want to note any important deadlines. For example, you might need to get work by the finance department finished before it starts work on year-end. Subscribe to Our NewsletterReceive new career skills every week, plus get our latest offers and a free downloadable Personal Development Plan workbook. Read our Privacy Policy Step 3: Decide Who You Need to InvolveYou can do the estimates yourself, brainstorm them as a group, or ask others to contribute. Where you can, get the help of the people who will actually do the work, as they're likely to have relevant experience to draw upon. By involving them, they'll also take on greater ownership of the time estimates they come up with, and they'll work harder to meet them. Tip:It's always a good idea to consult with others about your project. You can confirm your assumptions with them, and it can encourage initiative. Doing so will also ensure that you don't miss something crucial – for fear of looking weak or feeling threatened by team members. See our article, Avoiding Management Self-Sabotage, for more on this. Step 4: Make Your EstimatesYou're now ready to make your estimates. We've outlined a variety of methods below to help you do this. Whichever methods you choose, bear these basic rules in mind:
Note:It's likely that your estimate following these principles will be longer than you want or are permitted to allow. But don't be tempted to be unrealistic and knowingly underestimate. Instead, look at removing wasteful steps using the Lean and 5S models. You may also be able to increase capacity, so that work can be done in parallel, or choose automated processes over manual ones. See our sections on Strategy, Team Management and Time Management for further guidance on supporting everyone in their individual productivity. Methods for Estimating TimeWe'll now look at different approaches that you can use to estimate time. You'll probably find it most useful to use a mixture of these techniques:
Tip:In the early stages of project planning, you often won't know who will do each task – even though this can influence how long the task will take. For example, an experienced developer should be able to develop a software module much more quickly than someone less experienced. You can build this into your estimates by giving best, worst, and most likely estimates, stating the basis for each view. Apply Your EstimatesOnce you've estimated the time needed for each task, you can prepare your project schedule. Add your estimates to the draft activity list that you produced in the second step, above. You can then create a Gantt Chart to schedule activities and assign resources to your project, and to finalize milestones and deadlines. Tip:If your project is complex, it's crucial that you highlight the tasks that can't be delayed if you're to hit your deadline. Use Critical Path Analysis and PERT Charts to help you do this. Key PointsYou need to estimate time accurately if you're going to deliver your project on time and on budget. Without this skill, you won't know how long your project will take, and you won't be able to get commitment from the people required to help you achieve your objective. More than this, you risk agreeing to impossibly short deadlines, with all of the stress, pain, and loss of credibility associated with this. To estimate time effectively, follow this four-step process:
Use a variety of methods to get the most accurate time estimates. What is the advantage of the bottomThe advantage of bottom-up estimating is that it leads to greater accuracy. This is exactly what Lance needs. The accuracy results because this approach takes into consideration each component of the project work.
What is the bottomBottom-up estimating is a management technique for determining the overall cost or timeline for a project by examining the work at the most granular level of detail, compiling all this information, and then coming up with an overall budget and timeline for a project that can be delegated to team members.
What are the advantages of bottomThe bottom-up approach is on the other hand a very time-consuming and costly method, but it gives a more accurate estimate of the project time and cost. By using the bottom-up approach, the cost and time frame is being calculated for every activity related to the project.
What is topBottom-up estimating approach: Allows teams to estimate how long each sub-task will take. This time then rolls up into an overall time-to-project-completion estimate. Top-down estimating approach: Starting with an estimate of how long the entire project will take, then breaking it down into the various tasks.
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