194 Part II: Planning Your Software Project and (Free web hosting music)
194 Part II: Planning Your Software Project and on the questions would have to go. It s difficult, if not impossible, to give an accurate estimate on anything if the requirements and scope of the project are not defined. As you progress through the project planning and gain more information about the project requirements, your estimates will be more reliable. Instead of a range of +75 percent to 25 percent, your next estimate may be +40 percent to 10 percent. Traditionally, ROM estimates have a nice way of coming back to haunt project managers. There s something mystical about the first number management hears when it comes to estimates. Be wary of ROM estimates. Creating a budget estimate While a ROM estimate is nice for conversations, it s impossible to use for any substantial software project plan. ROM estimates are little more than wishes and blue sky. In order to create an accurate estimate, or at least a more accurate estimate, you need more information. The next level of estimating for a project is to create a budget estimate. The budget estimate is somewhat more reliable because you ve got a better grasp on what s actually to be included in your software as you spend more time gathering requirements. The qualifier for budget estimates is typically 10 percent to +25 percent. Budget estimates are typically created based on historical information. If you ve done a similar project in the past, you can use this historical information to predict what your current project is going to cost. Using historical information is called analogous estimating or top-down estimating because you start at the top of the project and you move quickly to the deliverables, drawing analogies to previous projects as you go. Again, although it s a great place to start, when used all alone, analogous estimating doesn t yield the most reliable results. We discuss analogous estimating in more depth in Chapter 8. Creating a definitive estimate The final, and most accurate, estimate type is the definitive estimate. Even its name sounds accurate. The definitive estimate requires a detailed decomposition of everything the project will create. It takes time to create and is also known as bottom-up estimating. Its qualifier is usually 5 percent to +10 percent. Figure 9-2 shows the range of variance customers can expect with a definitive estimate.
From our experience, we can recommend PHP Web Hosting services, if you need affordable webhost to host and run your web application.