Precision vs. accuracy: Definitions and tips

People love to conflate ‘accuracy’ and ‘precision’, but they’re wildly different things. Something can be precise but not accurate — and accurate but not precise. Nailing both is important in daily life, but in the world of business, it’s mission-critical. 

Let’s take a closer look at what these two very different terms mean, how to measure them, and how to choose between the two when you can’t have it all. 

What’s the difference between accuracy and precision?

When we talk about measurements and performances, two words often crop up: accuracy and precision. Similar sounding terms that are often used interchangeably — but in application, they’re not even close (no pun intended). 

Accuracy vs. precision 

Accuracy means how close you are to your target. 

Let’s say you’re measuring a door. You get a measurement of eight feet high. 

• If the door is truly eight feet high, then you are accurate. 
• If the actual length is eight and a half feet, then your measurement is quite accurate. 
• But if the true length is six feet, then your measurement isn’t accurate at all.

Precision, on the other hand, is about consistency. It refers to how close your results are to each other, regardless of whether or not you hit the target. 

Think about a chef making pancakes. 

• If every pancake is six inches across, the chef is being precise in their pancake size. 
• If the desired size is 10 inches, then they are precise and consistent but not accurate.

TL;DR: Accuracy is about hitting the right target, while precision is about hitting the same mark over and over again.

Accuracy vs. precision: The classic bullseye example

Let’s talk about this with a simple example — the bullseye analogy. 

Imagine you’re chucking darts at a dartboard.

• Accuracy and hitting the bullseye: If you aim for the bullseye and your darts land there, then congratulations — you’re right on the money. That is accuracy in action. Could you be on the path to the championships? That all depends on whether you can repeat the performance, aka whether you can make your performance precise. 

• Precision and grouping of arrows: Now imagine all your darts land in a tight cluster, but this cluster is on the edge of the board. It’s nowhere near the bullseye and certainly not earning you points. You’re precise, because your shots are consistently landing in the same spot, but you’re not accurate. Those championship dreams don’t look so good. 

How to visualize accuracy vs precision

1. High accuracy, low precision: Your darts hit all around the bullseye, but they’re not close to each other. You manage to hit the target accurately overall, but the spread is wide.

2. Low accuracy, high precision: Your darts are grouped tightly together but are off in the corner of the target. You are consistent, but you’re consistently off the mark.

3. High accuracy, high precision: All your darts are in a tight group right at the center of the bullseye. You are hitting exactly where you aim, and you do it consistently.

4. Low accuracy, low precision: Your darts are all over the place — no consistency and not hitting the target where you wanted.

(Image source)

Accuracy vs precision: three relatable, real-world examples

Let’s look at some examples from everyday life. These will help you see how these concepts play out in different settings.

1. Cooking with recipes

Picture yourself trying to make pancakes. If you measure the ingredients accurately according to the recipe, your breakfast will taste *chef’s kiss*. This shows accuracy. But if you consistently use a little too much flour every time, your pancakes are precise in the amount of flour used but not accurate to the recipe. Accuracy ensures your cooking tastes right, while precision means you get the same taste every batch (even if it’s not the intended one). 

2. Filling up gas

Here’s another scenario. You’re at the gas station filling your car. If the pump is accurate when it stops at 10 gallons, you have exactly 10 gallons in your tank. That’s accuracy — getting what you expect. But, if you notice every time you fill up, the pump stops a bit early or goes a bit over, but always by the same amount, that’s precision. It consistently errs by the same margin. Accurate pumps give you the right amount of gas, while precise pumps give you a consistent amount, but not necessarily the correct one. 

3. Weather forecast

Ahh, the weather forecast. Perhaps the least accurate prediction service in existence. Let’s say the meteorologist predicts rain, and every day, there’s rain — that means their prediction is (shock!) accurate. But if over a week they keep predicting rain and every day, it’s sunny, the forecasts are precise but not accurate. Ideally, you want your weather forecasts to be both precise (so you can see consistent patterns) and accurate (so you know whether to bring your umbrella).

Why is accuracy important?

Accuracy affects your ability to make sound decisions and build trust with customers and stakeholders alike. 

Smarter decision-making

When you have watertight data, you can analyze trends and make strategic plans with confidence. 

Example: Imagine you’re a company forecasting sales for the next quarter. If your data on customer behavior and past sales is accurate, you can predict revenue, adjust your strategies, allocate resources, and so on, with a fair amount of confidence. It’s no crystal ball, but it’s the next best thing. 

Happier customers

When you understand customer needs and deliver exactly what you promised, you build a stronger relationship with them. 

Example: In eCommerce, correct delivery times are essential. If a business promises a two-day delivery based on accurate logistics planning, meeting this timeline is more likely, and customers will be happy. This frees up your customer service team and protects you from returns. On the flip side, bad information can lead to wrong deliveries, returns, unhappy customers, damaged reputation, and ultimately, a loss of revenue. This is especially important if you’re a startup, where building trust is essential to building a loyal customer base. 

Why is precision important?

Precision is equally important in the business world because it means you’re bringing consistency and quality to the table.

Consistency in quality

Precision in processes/measurements means that every product or service meets the same high standards. If you want a reputation for quality, it’s a must.

Example: In manufacturing, precision in the production process means that each part meets strict specifications. For instance, a car manufacturer relies on precision in the assembly line, so every engine fits perfectly into the car frame. This consistency is essential for safety, performance, and reliability. 

Reduced waste

If you’re constantly following precise standards, you can optimize your processes, cutting back on wastage and redos. 

Example: In the pharmaceutical industry, precision in measuring the amount of active ingredients in each tablet is not just a matter of quality, but also customer safety and legal compliance. Getting those measurements right to the milligram means every batch is effective and safe. 

How do you measure accuracy and precision?

So, how can you keep an eye on accuracy and precision in real life or work? It’s all about tracking and consistency.

How to measure accuracy 

To measure accuracy, compare your results to the true value or the standard. Here’s how:

• Work out the error: Subtract the true value from your measured value. For example, if you measure a cat to be 100 cm from head to tail, but its actual length is 102 cm, your error is 100 cm — 102 cm = -2 cm.
• Use percentages: It helps to express this error as a percentage of the true value. In the table example, the error is 2 cm off 102 cm, so the error percentage is (2/102) x 100% ≈ 1.96%.

This gives you a clear idea of how close you are to the desired result. A lower error means higher accuracy.

How to calculate precision 

Measuring precision is about finding out how much your results vary from each other. Here’s a simple way to track it:

• Calculate the range or standard deviation: If you take several measurements, you can use the range (difference between the highest and lowest values) or the standard deviation (a statistic that tells how spread out your numbers are).
• Consistent results mean low variability: E.g., if you measure that table several times and get 100 cm, 100.5 cm, and 99.5 cm, your measurements are pretty precise. The range is 1 cm (100.5 cm to 99.5 cm), indicating good precision.

Top tip: Use project management software (like Backlog) to automatically track these metrics over time. This gives you a visual of how you’re improving or what needs a tweak. It’s all about getting the right balance based on what’s most important for your task or project.

So which is more important — accuracy or precision?

The short answer? It really depends on what you’re doing.

When accuracy matters most

If you’re doing something where the right outcome is critical, go for accuracy. 

Let’s say you’re a nurse in a busy ICU. You need to measure out the ingredients for a medication. Getting those powders and pills right to the milligram could be the difference between life and death. Similarly, if you’re buying a lovely new wardrobe to fit in a specific space, you need accurate measurements to guarantee you’ll get your new furniture in your chosen spot.

When precision matters most

If you’re in a situation where consistency is key, opt for precision. This is a must in manufacturing and quality control processes. For example, let’s say you’re producing nuts and bolts in a factory. They all need to be exactly the same size and shape to fit correctly. Even if your machine’s settings are slightly off, as long as they are consistently off in the same way, both components will still function together.

Ideally, both

In a perfect world, you’d always have both high accuracy and high precision. This means that your measurements are not only close to the true value but also consistent every time. However, if you absolutely have to choose, think about the end user. 

Tips on choosing between accuracy vs. precision

• Think about the consequences of errors: If being off by a little bit means big problems (like in medical or safety-critical fields), prioritize accuracy.

• Look at the need for consistency: If you need to maintain a standard quality or ensure interchangeable parts, prioritize precision.

• Resource and time constraints: Sometimes, achieving high accuracy requires more time and resources. If you’re limited, improving precision might give you the best compromise.

• Think about the end user: What matters most to them? If you’re a chef, being precise means your dishes are consistent for every customer. If you’re cooking for yourself, adjusting for accuracy means your dish will taste just the way you want it. 

How project management tools can help

Project management tools help you keep all your tasks, docs, and comments in one spot. This means you can easily see what needs to be done, who’s doing what, and when things are due. But perhaps most importantly where matters of accuracy and precision are concerned, PM tools automatically measure your work as you go. 

With Backlog, you can see at a glance how much of the project is behind you, what’s in progress, and what’s yet to start. This is great for keeping things precise: you can see if parts of the project are lagging and adjust your plans to stay on track. And, by keeping a detailed record of tasks and deadlines, you can nip errors in the bud (boosting accuracy) and make sure the team’s following processes to a T (boosting precision).

After your project is done and dusted, these tools can help you look back and see what went well and what didn’t. This feedback loop is the best way to improve your processes, and most importantly, make your next project even better. Think of it as a way to fine-tune your accuracy and precision today, and for all your projects to come.