A key skill for project managers is being able to make accurate predictions. It can be easier to keep projects on plan and under budget if you use advanced estimation methods. One way to make sure your project figures are reliable and correct is to use three-point estimating.
What is three-point estimating? This piece explains what it is, how to use it to make estimates, what its benefits are, and gives an example.
How do I estimate with 3 points?
The three-point method of estimating looks at three different estimates to figure out how long a job or project will take:
The most hopeful guess
The worst possible guess
The most likely guess
The hopeful estimate thinks that everything goes as planned. There are risks that could cause the low estimate to take longer than expected. Based on the estimator’s best guess, the most likely estimate is somewhere between the hopeful and pessimistic ones.
Pros of guessing with 3 points
Better accuracy and planning. Using more than one estimate helps project managers get a better idea of what might happen, which makes it easier to keep track of funds and resources.
Better decisions: When managers think about the best and worst-case scenarios, they can picture the risks and chances, which helps them make smart choices.
Stakeholders don’t like spending surprises, so you should be better at managing their expectations. With 3-point estimating, people are shown different possible results, helping them get ready for both the best and worst cases.
Analysis of historical data: Project managers can make their estimates better by using historical data to improve the most likely, most pessimistic, and most hopeful estimates. Over the course of months and years, this makes project management more accurate and effective.
Figure out the formula
To figure out how long a job or project is likely to take, use the following formula.
Time expected to take = (highest possible guess plus 4 times the lowest possible guess plus the worst possible guess) ÷ 6
The hopeful and pessimistic estimates each add one sixth to the total weight. The most likely estimate has four sixths of the weight.
There are other 3-point formulas that can be used to guess how long a job or project will take, how much it will cost, or how much work it will require.
Another common formula that takes into account possible results is the triangular distribution. This method uses the following formula to figure out the expected duration based on the optimistic, pessimistic, and most likely durations:
What the difference is between triangle distribution and three-point estimation
There are some key differences between 3-point estimating and triangular distribution when it comes to figuring out how long a job will take.
This makes the distribution triangular
Three-point guessing lets you think about a wider range of possible outcomes, while triangular distribution assumes that outcomes are more evenly spread out around the most likely estimate. It helps when there isn’t a lot of information about how a job might turn out.
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How do you use three-point estimating?
A way to make projects is to use three-point estimates. It is a collection of three different types of estimates:
Optimistic estimate: This is the value that you get in the best-case scenario, if everything goes as planned and there are no problems with the job.
Assumption of bad outcomes: This number tells you what outcomes you can expect if bad things happen during your project. This estimate can be thought of as the worst thing that could happen, where everything goes wrong.
This third estimate is a fair one. You will run into some problems, but for the most part, everything will go as planned. It plans for things that didn’t go as planned, which are likely to happen during the whole project.
3 method for estimating
Getting estimates right can help projects work. Three-point estimates can help project managers do their jobs better and faster. This method is more likely to give you a more accurate number because it takes three different situations into account.
This method can help you figure out your estimate by giving you a weighted average of your optimistic, realistic, and pessimistic estimates:
How to figure out three points of info
As the project manager, you can give the final cost estimate for the project by taking into account what each team member has done. The steps below make this process simple and easy to carry out:
1. Look over the job
Help the other people on your team figure out the good and bad things about their jobs. To make sure your project is a success, you should think about what could go wrong and take steps to deal with any risks or problems that come up. Taking this method can help you make decisions ahead of time.
2. Give each estimate the info it needs.
In this step, you’ll ask your team to give you three estimates for each job. These estimates should include:
Optimistic estimate: First, ask team members to think of the shortest amount of time they think it could take to finish the job, based on their experience and the assumption that they won’t have to deal with any problems.
Pessimistic estimate: Second, ask team members to think about all the problems they might face on the job and how long those problems might take to solve. After that, they can guess how long it would take them to finish their work if all of those problems happened.
Realistic estimate: Finally, ask the team to find the middle number between these two figures. There is a way for them to do this: add up their optimistic and pessimistic predictions and divide by two.
3. Figure out the end estimate and the standard deviation.
It is important to pay close attention to the mean negative time when you make your final guess. Once you have the numbers, you can share them with your team and sponsors by making an estimation presentation. Once you’ve finished your three-point estimate, it’s important to find the amount of accuracy. The three-point estimation method is very accurate, and its main goal is to make accurate estimates that promise project success by finding any problems ahead of time and fixing them.