Learning How to Estimate
In many areas of life and work, estimating is a skill that will help you be more effective and efficient. If you can estimate accurately and quickly, you can more easily manage your day, a particular project, your relationships, your budget, and so many other facets of living and working. Estimates help you to make sense of problems, reason abstractly, construct viable arguments, model with mathematics, use appropriate tools, focus on precision, make use of available structure—and so many other benefits.
Estimating is primarily taught as a math skill but it is more of a mind skill. The first and greatest result of being able to estimate is to determine the reasonableness of your answer. That is, does your solution fall into a reasonable range? This is tremendously practical. At the grocery store, do you estimate you have enough money in your wallet to pay for everything in your cart? Or do you have enough time at work to complete the tasks you’ve been asked to finish. Or do you have enough people to engage the project your client wants you to take on?
If you work in construction, you realize that you live in a world of estimates, all day every day. Once you understand that estimation is valuable, then there are several steps you can take to build your skill in this area.
Round it off. Learn how to take precise measures and deal with them more generally. Nine is almost ten, and ten is a much easier number to work with than nine. You can more easily think in blocks of ten than in multiples of nine. When thinking of hours of work, you can say four hours or eight, but it is far easier to think in half-days and days. Sixteen hours on a project is two days. When looking at any unit of measure, think about whether rounding to a whole number or a more basic until will help you estimate.
Revisit the past. Your actual experience in the past will be very helpful to you in estimating in the future. When you come to a project similar to what you have done before, go back and look at the actual time, people resource and monetary expenses involved. Maybe you originally thought your new project would consume three days, but in the past it has taken an average of four. Or maybe you think an analysis will cost $1,000, but in previous iterations it has usually cost about $600. Past experience can help you estimate future needs.
Think in blocks. Five people working on a project all day for five days is 25 people-days, or equal to about one person working for a month on the project. Use your multiplication and adding skills to compile projects into various blocks of time, money or other resources. This will make it simpler to estimate cost, man hours and other aspects.
Guess, then measure. Hone your estimating skills by looking at something, making a rough estimate in your mind, and then measuring precisely to see how close you were. As you compare your estimate to the actual measurement, over time, your estimating skill will get more accurate. Does the room you are in look like it’s about 10 x 12 feet? Now measure it. How far off were you? Does the box you are holding feel like it’s about 10 pounds? Now weigh it.
If you can estimate the time something will take, the amount something will cost, or the measurement of a given object or resource—and be accurate in those estimates—it will positively affect your day, your work, your life. And it will keep you from making significant mistakes. If you multiply 523 x 34 and get an answer of 177,820, you will know, for instance, that this can’t possibly be correct. If you multiply round numbers 500 x 30 you get 15,000—so the answer must be in that neighborhood, and your first number is way off.