There's also the classic method of providing a best, worst and expected case estimate for each item and then computing a result
computed_result = (b + 4e + w)/6
You can use that to demonstrate how you derived your estimates.
HOWEVER, if you provide a range of time; all the client/sponsor/stakeholder is going to see is the lowest value. No mater what you say. So keep the range secret, and advertise the computed result.
我使用过 Merlin2，它是 Mac 的项目管理产品。 当您开始一个新项目时，它会询问您开始日期和结束日期 - 这看起来是固定的，但是当您查看项目计划检查器时，您会发现开始日期和结束日期实际上都有一个“最早日期”和“最新日期”和可以编辑的结束日期。 默认情况下，它将开始日期添加到“最早开始日期”中，将结束日期添加到“最晚结束日期”中 - 您可以根据需要进行调整。
I've used Merlin2 which is a project management product for the Mac. When you are starting a new project it asks you the start date and end date - which look fixed, but when you look at the project plan inspector you see that there is actually an "Earliest Date" and "Latest Date" for both the Start and End dates which can be edited. By default it adds the start date into "Earliest Start Date" and the end date to "Latest End Date" - and you can tweak as necessary.
"Some people have suggested that when doing an estimate one should make a lower and upper range on the expected time to delivery."
But what do your project stakeholders want? Will a range help them decide to fund your project?
Ranges don't really mean very much. Further, most people ignore the range and either see the low or the high number. Optimists have "happy-eyes", see the low number, and complain when you don't hit it, even if you're under the high number. Pessimists see the high number, say it's too big, and demand you replan the project to make the number smaller.
How -- precisely -- will a range help you? Who needs the range? What information will the range help them with? What decision do they have to make that requires a range?
I suggest that you plan each piece realistically.
Further, prioritize your project. After prioritizing, you'll see that there's some essential stuff, some important-but-not-essential stuff, and some optional stuff. This is your range. Cost to do the essential stuff is low. Cost to do important-but-not-essential is in the middle. Cost to do the optional stuff is high.
When someone asks you to "replan", you trim optional stuff.
It isn't a simplistic range. It's a realistic view of what you'll get done and what value it has.
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Joel 在其 FogBugz 6.0 软件中大力宣传循证调度。
Joel touts Evidence-Based Scheduling in their FogBugz 6.0 software.
还有一种经典方法，即为每个项目提供最佳、最差和预期情况估计，然后计算结果。
您可以使用它来演示如何得出估计值。
但是，如果您提供一定的时间范围； 客户/赞助商/利益相关者将看到的只是最低的价值。 不管你说什么。 因此，请对范围保密，并公布计算结果。
There's also the classic method of providing a best, worst and expected case estimate for each item and then computing a result
You can use that to demonstrate how you derived your estimates.
HOWEVER, if you provide a range of time; all the client/sponsor/stakeholder is going to see is the lowest value. No mater what you say. So keep the range secret, and advertise the computed result.
我使用过 Merlin2，它是 Mac 的项目管理产品。 当您开始一个新项目时，它会询问您开始日期和结束日期 - 这看起来是固定的，但是当您查看项目计划检查器时，您会发现开始日期和结束日期实际上都有一个“最早日期”和“最新日期”和可以编辑的结束日期。 默认情况下，它将开始日期添加到“最早开始日期”中，将结束日期添加到“最晚结束日期”中 - 您可以根据需要进行调整。
I've used Merlin2 which is a project management product for the Mac. When you are starting a new project it asks you the start date and end date - which look fixed, but when you look at the project plan inspector you see that there is actually an "Earliest Date" and "Latest Date" for both the Start and End dates which can be edited. By default it adds the start date into "Earliest Start Date" and the end date to "Latest End Date" - and you can tweak as necessary.
“有些人建议，在进行估算时，应该对预计交货时间制定一个下限和上限。”
但您的项目利益相关者想要什么？ 范围会帮助他们决定资助你的项目吗？
范围实际上并没有多大意义。 此外，大多数人都会忽略这个范围，要么看到较低的数字，要么看到较高的数字。 乐观者有“幸福的眼睛”，看到低数字，并在没有达到目标时抱怨，即使你的数字低于高数字。 悲观主义者看到这个数字很高，说它太大了，并要求你重新规划项目以减少这个数字。
准确地说，范围将如何帮助您？ 谁需要范围？ 该系列可以帮助他们获得哪些信息？ 他们必须做出哪些需要一定范围的决定？
我建议你切合实际地计划每一件作品。
此外，确定项目的优先顺序。 确定优先级后，您会发现有一些必要的东西，一些重要但非必要的东西，以及一些可选的东西。 这是你的范围。 做必要事情的成本很低。 做重要但非必要的事情的成本处于中间位置。 做可选事情的成本很高。
当有人要求你“重新计划”时，你会删除可选的内容。
这不是一个简单的范围。 这是对您将完成的工作及其价值的现实看法。
"Some people have suggested that when doing an estimate one should make a lower and upper range on the expected time to delivery."
But what do your project stakeholders want? Will a range help them decide to fund your project?
Ranges don't really mean very much. Further, most people ignore the range and either see the low or the high number. Optimists have "happy-eyes", see the low number, and complain when you don't hit it, even if you're under the high number. Pessimists see the high number, say it's too big, and demand you replan the project to make the number smaller.
How -- precisely -- will a range help you? Who needs the range? What information will the range help them with? What decision do they have to make that requires a range?
I suggest that you plan each piece realistically.
Further, prioritize your project. After prioritizing, you'll see that there's some essential stuff, some important-but-not-essential stuff, and some optional stuff. This is your range. Cost to do the essential stuff is low. Cost to do important-but-not-essential is in the middle. Cost to do the optional stuff is high.
When someone asks you to "replan", you trim optional stuff.
It isn't a simplistic range. It's a realistic view of what you'll get done and what value it has.