Estimating effort: Part 2 This article is part of a series on how to estimate effort. Since I found that many people mistakenly use terms like budget and estimate as synonyms, I decided to focus on definitions. Here’s a quick recap of the key definitions I will use: Estimate. A well-informed assessment of an uncertain event. An informed assessment means that you have a basis for your estimate. Uncertain recognizes that different outcomes may be possible. Effort. Effort refers to the effort of a member of a project team. Effort is usually measured in terms of staff hours. Budget. Management metric that uses the effort estimation as one of the key inputs. Baseline. A time-phased budget which has received all approvals. What are you estimating Let’s begin with a simple example to establish a conceptual foundation. It may seem obvious, however, the first step in developing an estimate is to understand what you are estimating. Let’s say that you were asked to estimate the effort and time required to paint your bedroom. Although it is a small task, there is still a lot of uncertainty.
- Do you need to paint the ceiling, the woodwork, or the walls?
- Are there windows that can be painted? Are there mullions?
- Is there furniture in this room? Is it possible to move it? Is it possible to move it? ?
- Is this part of the activity? How about going to the shop to purchase the paint?
- How many coats do you need? What special finishing is required (e.g. marbleizing)?
- Are you going to have anyone help? Or will you do all the work?
These questions can be difficult to answer. There are a few options:
- You can decline to provide an estimate.
- An estimate can be prepared that allows for a lot of uncertainty.
- These questions can be answered by making assumptions and then estimating based on these assumptions.
- Before preparing an estimate, you can reduce uncertainty by asking questions.
As long as your stakeholders are aware of which approach you’re using, any of these approaches can be accepted. ?Most likely, you will use a combination of approaches. You will make reasonable assumptions. And you will always document your assumptions! You will ask questions. You will then use your best judgement. Range estimates. Range estimates can help you improve the utility of your effort estimates. How does a range estimate work In its simplest form, a range estimate is a way to estimate the value of your effort. In the example of painting your bedroom, you might estimate 2-3 hours, assuming that the work is limited only to applying paint to the walls. Range estimating doesn’t require you to know how much effort will be required. It doesn’t take up a whole day of your time, but you do need to be aware of this fact. This is not a simple task that can be done in a few minutes. You have made a good estimate as long as the actual result takes between 2 and 3 hours. Even if the actual result is not within that range, it still qualifies as a good estimate. It was the best estimate you could make given the information available at the time. You can also learn from any?variance (an actual outcome that is outside of the predicted range) and use this information to improve your future estimates. Range estimates take the guesswork out of the estimation process. It can be difficult to choose between 2 and 3 hours if you are used to using single-point estimates. Even a 2-point estimate of 2 can be difficult.