Accuracy Vs. Precision

[Coraly De Leon]

Hey !

I know Dr. Lavelle went over the definitions of accuracy and precision during lecture, but I am still a little confused on how to differentiate since the definitions have quite similar wording. Can someone clarify ?

[Kaira Shibata 1E]

Hi!
Accuracy and precision may seem very similar but they are different. Accuracy is the closeness to the true value. For instance, if you calculated 4.789 and 4.699 and the true value you are trying to calculate is 4.710, your results would be considered accurate. They are close to the true value. On the other hand, precision is how close your results/values are to one another. We will use the same true value of 4.710, but let's say you got 7.089 and 7.091 as your calculations. These would be considered precise because they are close to one another, but not necessarily close to the true value of 4.710.
I hope that helps!

[Vincent Nguyen 3G]

Precision is more about getting a group of measurements that are close together while accuracy is about actually being close to the real value. For example, say I am using a scale to weigh a 30.0kg weight. I want a measurement that is within 2kg of the real weight. If I weigh it 3 times and get 15.1kg, 15.2kg, and 15.0kg, then the scale is precise because the measurements are close, but it is not accurate because it is not even within 2kg of the real weight. If I use another scale, weigh my weight 3 times, and get 28.4kg, 31.9kg, and 30.4kg, then my scale could be called accurate because it is close to the real value, but it is not precise since the different measurements are far apart. Precise and accurate would be something like 30.1kg, 29.9kg, and 30.0kg. Inaccurate and imprecise would be like 100.0kg, 0.2kg, and 21.6kg.

[cecilia1F]

Hi!
I know that for me this diagram using the dartboard as an analogy really helped me to understand the difference between the two:
https://soluzionesolare.com/guides/diff ... precision/

[Grace Chang 1E]

Hello! For accuracy vs. precision, it really helped for me to look at the diagram of the four targets Dr. Lavelle showed in the lecture.

Precision is more about how close the measurements are to each other, while accuracy is about how close the measurements are to the true value.

So for example (using the target diagram), if precision is high but accuracy is low, the dots will all be clustered very close together but far away from the center of the target. If precision is low but accuracy is high, the dots will be quite close to the center of the target, but they'll be at quite a distance from each other.

I hope that helps!

[Hannah Carsey 1B]

When I think of precision vs. accuracy, I first start with the given definitions and then try to think of these definitions in my own words. For precision, it is defined as seeing how close to one another different measurements are, and this definition is basically telling you that precision has to do with comparing different measurements and seeing if these measurements are very different from each other or are very similar. If measurements are very different from each other, the measurements are not precise, if the measurements are very close to each other, the measurements are precise. In terms of accuracy, it refers to a measurement's closeness to the true value, which means that accuracy is seeing how close one measurement or a group or measurements are to the true, expected, theoretical, or ideal value. If a measurement is not close to the ideal value, the measurement is not accurate, if a measurement is close to the ideal value, the measurement is accurate.

[Irene Kang 3F]

Accuracy is trying to get the specific quantity or measurement. For instance, if your goal is to get 10g, then getting 9.9 or 10.1 g would be accurate.

Precision is when all your trials are close to each other. For instance, if you had to do something 10 times and get the measurement of 10g and all 10 results end up being 6.5g or 6.6g, you have high precision. This is because all your trials are similar to each other, but they are just not accurate.

This is in terms of measurements but I think using the darts and bullseye method is the best way to picture the differences.

[Meagan Kimbrell 1I]

I posted this on another question very similar to this but.. As said before, the dart board example is a great way to remember the difference between accuracy an precision. Professor Lavelle utilized it in his lecture slides, but here is a link that displays the example and has some more information about the topic: https://manoa.hawaii.edu/exploringourfl ... s-accuracy
Figure A represents neither accuracy nor precision
Figure B represents precision
Figure C represents accuracy
Figure represents both accuracy and precision
Hope this helps!!

[Terrence Chi]

Accuracy refers to the closeness of a measured value whereas precision is how close repeated measurements are to each other. For example, the more measurements you make, there will be a higher outcome of precision with smaller error.

[Tyler_Kim_2G]

In lecture, we learned that precision describes how close measurements are to one another and accuracy refers to how close a measurement is to an actual or known value. I found the target example to be helpful, so if we refer back to it, if all the darts are bunched together near the bullseye, then there is high precision and high accuracy. However, if the darts are scattered haphazardly across the target, then there is low precision and low accuracy.

[Matthew Vu 3C]

Accuracy refers to how close something is to the true value, whereas precision refers to the how much variation there is in your measurements. For example, if something weighs 1 gram, and you measured the sample to be .99 grams, you would be accurate. If you measured it to be .99 grams several times, you would also be precise. However, if you measured it to be .99 grams, then .75 grams, then 1.3 grams, etc, you would not be precise.

[Jayden Tan 2L]

Hello!!!

Think about playing darts. If you constantly hit one part of the board, but you clearly aren't hitting the bullseye, you aren't accurate. You are precise. Accuracy is a measurement of how close you are to the true value, or in this case, the middle of the dart board. Precision means that doing something continuously and getting the same results. Precision and accuracy may seem like the same thing, but once you imagine a dart board, like the one from lecture, it is easier to grasp the concept!

[Eric Sun 2G]

The way I think about Accuracy vs Precision is that precision is just like how consistent something is. On the other hand, I would think of accuracy as how correct something is.

[505734174]

Accuracy describes how close a result is to the true value (ie how correct it is) while precision describes how close measurements are to eachother. If you remember the target diagrams from the lecture, they were a really good visual differentiation between the two concepts.

[Erin Woolmore 1C]

I always think of accuracy as how close the results are to a specific goal/value (much like the darts example), and precision relates to how consistent/close to a similar result you are in your results, even if it is not the true value.

[Crystal Ma 2J]

Hi,
Think of accuracy as how close a measurement is to a specific value (for example, when a class is measuring 5 grams of a substance, they would all measure close to 5 grams) while precision is how close a measurement is to other measurements (for example, if a class was to measure 5 grams of a substance, but everybody measured close to 8 grams instead, they would be precise but not accurate).

[Shaleena 3C]

Hi! So the difference is that precision is how close the MEASUREMENTS are, vs accuracy which is how close the measurements are to a value. Just two different comparison points.

[Michelle Argueta 1E]

Hi! I totally understand you about the close proximity between the definitions of 'accuracy' and 'precision.' The way that I differentiate accuracy and precision is that ACCURACY is how CLOSE the MEASUREMENT is to the TARGET, while PRECISION is how close MEASUREMENTS are to EACH OTHER.

[krish shah]

I'm understanding the difference, but was wondering when where there will be a need to apply these definitions in class; within what type of problems will the knowledge of this be needed?

[Helen Ringley 2E]

Hi!
I know a lot of people already responded to this, but I feel like it's also important to mention that this also has a lot to do with scale. If you measure 11.0 and 11.5, and the true value was 11.2345, the measurements might be accurate but they are not very precise. But if your true value is 11.2345, and you measure 11.7500 and 11.7650, you may be a little less accurate but you are far more precise.
- Helen Ringley 2E

[Helen Ringley 2E]

Someone else asked about how these might be applicable in real life, and I think that Dr. Lavelle said during experiments, precision means that each measurement and step is done the exact same way for different samples. That way, all of your results are very close together and you avoid variability. Accuracy, in a real life setting, has more to do with whether or not the experiments you are doing yield results that are close to the true value. So for example, if you are burning cheetos to determine calories, if you burned each cheeto the exact same way and measured the results the exact same way and made sure that no heat escaped, you would be precise. However, if you were measuring on a scale that wasn't calibrated, the results might not be accurate, even though they were precise. So they are kind of related but they also have different consequences during real-life experiments.
I hope this makes sense!
-Helen Ringley 2E

[705573518]

The target analogy is helpful. Accuracy is hitting bullseye or close to it. Precision is if you hit far away from bullseye but continue to hit that same place over and over again.

[705573518]

The target analogy is helpful. Accuracy is hitting bullseye or close to it. Precision is if you hit far away from bullseye but continue to hit that same place over and over again.

[Charlie Sjogren-Black]

Hey !

I know Dr. Lavelle went over the definitions of accuracy and precision during lecture, but I am still a little confused on how to differentiate since the definitions have quite similar wording. Can someone clarify ?

How I think of it is that precision is how easily you can recreate the same results (ex. rolling a dice and getting 2 over and over) versus accuracy which is ability to get close to an exact ("true") value (ex. wanting to roll a six and getting a six.)

[Sasha Gladkikh 2A]

To reiterate, accuracy and precision are alike only in the fact that they both refer to the quality of measurement, but they are very different indicators of measurement.
- The precision of measurement indicates how close to one another the measurements are.
- The accuracy of a measurement is its closeness to the true value.

The following website provides a very clear illustration of the difference between accuracy and precision through the target analogy:
http://www.antarcticglaciers.org/glacia ... l-geology/
- The top-left target board represents low accuracy and low precision: all darts are scattered and all over the target board.
- The bottom-left target board represents high accuracy and low precision: all darts are close to the bulls-eye, but they are scattered.
- The top-right target board represents low accuracy and high precision: all darts hit the side of the target board, close to one another.
- The bottom-right target board represents high accuracy and high precision: all darts exactly hit the bulls-eye.

[Valerie M Dis 2E]

The target analogy is a good way to look at it. High accuracy would be hitting the bullseye. High precision would be consistently having all of your arrows hit a spot far from the bullseye but close together.

[Holly Do 2J]

There are many great ways to explain the difference between accuracy and precision. An example of this would be if the correct answer to a problem happens to be 2:
- Accuracy would mean that your values fall consistent of each other but not with the correct value. EX: 5,5,5,6 would be more accurate
- Precision would mean that your values fall near the correct value. EX: 2,3,2 would be more precise
- NOT accurate or precise EX: 8,10,5,54,67 since they are no where consistent or near the true value
- Accurate and Precise: EX: 2,2,2,2,3,2,2 since the values are consistent and are near/exact to the true value

[105784203]

Hey !

I know Dr. Lavelle went over the definitions of accuracy and precision during lecture, but I am still a little confused on how to differentiate since the definitions have quite similar wording. Can someone clarify ?

So precision is like being able to get the same result consistently, but this does not mean that the result is correct. Accuracy, on the other hand, means that you get the correct or close the correct answer, albeit not consistently.

[105743571]

Precision is how close data points are to one another, whereas accuracy is how close values are to the true value. For instance, if the true weight of an object is 10 kg, but your data values are:
15, 16, 15, 14, 15
Your data values are close to another (hence precise), but not accurate to the true value.
But if your data values are:
10, 11, 10, 11, 10,
Your data values are close to one another and to the true value, hence both precise and accurate.

[Arjun_Anumula_3E]

The dartboard analogy helped me a lot.

If all the data is concentrated around 1 spot, regardless of how far this may be from the true value, we would say the data set has a high level of precision

If all the data averages out to the true value, regardless of how far each individual data point may be from the true value, we would say the data set has a high level of accuracy.

[Veronica Larson- 1I]

Accuracy and precision definitely seem very similar at first glance, but they're actually quite different. Accuracy is about how close the results are to the true value, but precision is about how close your data points are to each other.

[arielle_cunanan3K]

Hi so when I think of accuracy versus precision, I think of it like answering a written prompt for a writing assignment. There technically is a wrong answer and a right answer (disregarding the nuances). When you write something similar to the correct answer that the teacher is looking for, you are being accurate. You are close to the true value (or answer) of the prompt. However, when you write multiple sentences about a specific topic, but isn’t close to “right” answer the teacher is looking for, you are being precise.

[Angela_Li_1J]

https://www.researchgate.net/profile/An ... e-true.ppm

I also have this same issue honestly, I feel like every year I take chemistry my teacher or professor always briefly go over it and then I forget what the difference is. But when I get confused between the two I always refer back to the chart above ^

[Nicole Ton 3C]

Hi! On one hand, accuracy is how close the collected values are to the true value or the goal. In the target analogy, this would be how close the points are to the center of the target. On the other hand, precision is how close the collected values are to each other. In the target analogy, this would be the spread of the points. So, if you keep taking measurements or collecting values but they are all vastly different from each other, then that means your points have low precision.

[Maggie Clark]

Accuracy- closest to true value, Precision- closeness of the values to each other

[Maggie Clark]

Accuracy- closest to true value, Precision- closeness of the values to each other

[Matthew Li 1B]

accuracy means how close did u get to your intended value while precision is about how close are each of your answers

[madelyn kelly 1I]

Precision conveys the how close multiple measurements are to one another, while accuracy refers to the closeness to the true values. When thinking of the target, low accuracy and low precision would be seen with arrows super spread out and far away from the bullseye. High accuracy but low precision would be displayed with arrows scattered from one another but in close proximity of the bullseye. Low accuracy and high precision would mean that the arrows were all close to each other, but far away from the bullseye. And lastly, high accuracy and high precision is when all the arrows are not only close to each other but all hit the bullseye.

[Jiayin Yola Yan 1G]

Hi!
Accuracy means how close the values are to the actual value, while precision refers to the closeness the values are to each other. Hope that helps!

[Ginny Ghang 1B]

When I think about accuracy, I think about how close the values are to the actual value. How close are the values to this one singular value that you are comparing it to. If the values are relatively around the true value, it has high accuracy. They data points do not necessarily have to be all clumped together.
When I think of precision, I think about how close the measurements are relative to each other. Something has high precision if the collected values are all relatively similar to each other. The data points are clumped together, but not necessarily clumped near the true value.

[Arya Bhalla 1H]

In everyday language we typically use accuracy and precision interchangeably. However, in the context of math and science, these terms are very different. Precision refers to how close measurements are to one another. For example, due to human error, I might repeatedly miscount the number of objects in a box and yet still get numbers that are close to one another each time. In this case, the precision would be fairly high but the accuracy, which is a measurement of how close the measurement is to the ACTUAL VALUE, would be off.

[Rebecca Preusch 2C]

I like to remember the difference by associating the term accuracy with actual because they both start with a. Accuracy refers to the closeness of data to the actual/true value. On the other hand, precision is the closeness of data to the other data points. It can get tricky to distinguish between the two because they aren't mutually exclusive, but I find remembering the a in accuracy stands for actual helps me keep them straight the best.

[Ayla3H]

In terms of an experiment, the accuracy of your values refers to the comparison of your value to its actual scientific value as stated in a textbook/professional research study. Precision, on the other hand, refers to how clustered/spread out your values are in comparison to each other (within your experiment).

It could be helpful to think of accuracy as a comparison of your experimental values to those of a more sophisticated study (external comparison) and to think of precision as a comparison between only your experimental values (internal comparison).

Hope this helps!