Why is accurate measurement important in science

Behavioral Measurement Database Services Blog. Fred B. Bryant, Ph. Loyola University Chicago. Modern society simply could not exist without measurement.

Twenty-first century civilization is inconceivable without the indispensable measurement tools on which everyday life depends. Time, size, distance, speed, direction, weight, volume, temperature, pressure, force, sound, light, energy — these are among the physical properties for which humans have developed accurate measures, without which we could not live our normal daily lives.

Measurement permeates every aspect of human life. Yet, ironically, we tend to take measurement for granted, and we fail to appreciate just how much we need and depend on our measurement tools. We overlook the importance of measurement because we are surrounded by it and have grown accustomed to it.

It is only when our measurement tools malfunction or are unavailable that we begin to appreciate just how important they are. However, if we were to try to live without measurement for even a single day, then we would quickly see just how vital measurement is in our everyday lives. A normal day would be impossible without measurement. As you go to bed , you begin to wonder how and when you will wake up the next morning to go to work.

Without measurement, there would be no clocks or alarms to awaken you at a selected time. But on the positive side, if there were no measures of time, then no one could ever know whether or not you were late for work. The very notion of being on time would vanish without measurement. After you wake up , you could not use an electric stove, oven, or microwave to make breakfast or coffee, because these devices rely on measurements of temperature or time to heat food and beverages.

Nor could you use a modern refrigerator, since refrigeration requires measurement to keep food and beverages at a preset temperature. In commuting to work , you could not drive because modern automobiles use onboard computers, which rely on measurement to control the ignition system, automatic transmission, brakes, engine temperature, throttle position, and mix of fuel and oxygen.

Nor could you know how much fuel, oil, or transmission fluid your vehicle had, for without measurement there would be no fuel gauge or dip stick to check these fluid levels. Even if you could drive a car, you could never know how fast you were going because you would not have a speedometer.

But, on the plus side, the police would never be able to pull you over for speeding because, without measurement, there would be no radar to enforce the speed limit. Indeed, there could be no speed limits without measurement. At work , you could not use a computer, since computers require measurement in order to operate. Nor could you use a land-line telephone, cell phone, or fax machine to communicate with others, because these devices rely on measurement to operate.

Forget about flying, or taking a bus, train, or ocean liner on an intercontinental business trip; and forget about traveling overseas. How does each of the following situations illustrate the differences between precision and accuracy? The oceanographer checks the weather forecast the night before her trip so she knows what to wear on the boat.

The other GPS units belonging to her colleagues on the boat also indicate that they are at the correct location. After an extensive search, the oceanographer finds the buoy 50 meters m from the boat. While on the way back to shore, the oceanographer throws in a fishing line to see if she can catch anything for dinner. She is lucky enough to catch a mahi-mahi.

When she pulls it out of the water, her colleagues estimate the weight of the fish. Their estimates are When they weigh the fish upon returning to shore, the actual weight is Write your own scenario illustrating the difference between accuracy and precision.

Swap your scenario with a classmate. A dart player can see how accurate his or her dart throws are by comparing the location of the thrown darts to the target, the bulls-eye of the dartboard. How is this model different from scientists who are measuring a natural phenomenon? Is there a way for scientists to determine how accurate their measurements are? An instrument that records accurate measurements or one that records precise measurements?

Accuracy and precision are both important if you want to measure anything and to make measurements you need some sort of instrument. It is crucial to have some idea about whether they are accurate or precise or hopefully both, depending on what you need to use the data for. In other words, precision is the agreement among several determinations of the same quantity.

The better the precision the lower the difference amongst the values showing that the results are highly reproducible. High precision is only achieved with high quality instruments and careful work. Left target: good precision but poor trueness; centre target: good trueness but poor accuracy; right target: good trueness and good precision, therefore good accuracy.

Accuracy is usually expressed either as a percent difference or a unit of measurement and can be positive or negative; the sign shows whether the experimental value is higher or lower than the actual or theoretical value. For example, 2. This distinction is not used in precision, since all values are experimental.