Precisely Wrong

In surveying, a measurement can be wrong right down to a fraction of an inch. That is a surveyor’s way of saying, “The numbers may look fancy, but that does not mean they are right.”

There are two words at the center of this concept: accuracy and precision. They are often used together, but they do not mean the same thing. Precision refers to how well something can be repeated. Accuracy refers to how close something is to the true answer. Put simply, accuracy means you are right. Precision tells you how tightly you can repeat the result.

The easiest way I know to explain it is with a bathroom scale. If you step on the scale three times and it says 184.2 pounds every time, that scale is precise. It is repeating itself down to a tenth of a pound. It is confident. It has no hesitation whatsoever. But if your real weight is 179, that scale is not accurate. It is just very consistent about hurting your feelings.

We see the same thing with a rifle, a dartboard, or a basketball shot. If every shot lands in the same tight group, that is precision. If that group is nowhere near the target, that is not accuracy. You are doing the same thing over and over. You are just doing it consistently wrong.

Anyone who has ever followed bad directions understands this too. Somebody may tell you, “Go exactly 2.6 miles, turn left, then go another 400 feet.” That sounds precise. But if they started you from the wrong gas station, you may end up in a bean field wondering what went wrong. That is precision without accuracy.

Surveying has plenty of these examples. We can measure a point with very good precision. Our equipment may give us repeatable numbers. The distances may check well. The angles may close. The coordinates may look clean on a screen. But the real question is, “Did we find the right boundary?”

An old iron pipe in the ground can be measured very precisely. So can a fence corner, a ditch, a tree line, a concrete post, or an old axle someone stuck in the ground 60 years ago. But just because we can measure it well does not automatically mean it is the property corner. That is where accuracy comes in.

Accuracy is not just about getting a good number. Accuracy is about getting the right answer.

With the technology available today, precision is becoming cheaper, easier, and more accessible to everyone. GIS mapping apps, consumer-grade GPS equipment, and drones can all seem exciting, official, and incredibly precise. They give us numbers, lines, coordinates, images, and measurements that look very convincing. But these tools do not replace the knowledge and expertise of a professional land surveyor.

A surveyor has to look at the deed, the adjoining deeds, the old surveys, the monuments, the occupation on the ground, and the history of the property. Sometimes the evidence agrees nicely. Sometimes the evidence and the title documents disagree. That is when the job becomes more than measuring precisely. It becomes judgment.

Another good example is elevation. Suppose someone runs levels across a property and does beautiful work. Every reading checks. Every calculation balances. Everything is neat and repeatable. That is precision. But if they started from the wrong benchmark, all of those neat numbers may be off. They did not necessarily perform poor work. In fact, they may have done very careful work. They just tied that careful work to the wrong starting point. That is the danger of being precisely wrong.

These are the reasons modern technology can be both helpful and misleading. Today, almost everything gives us numbers. Phones give coordinates. Cars give distances. Apps show property lines. Maps let us zoom in close enough to count fence posts. We have gotten used to things looking exact. But exact-looking is not the same as correct.

A number with several decimal places feels trustworthy. A line on a screen feels official. A measurement that repeats feels reliable. And sometimes it is. But sometimes it is only precise.That distinction matters when land is involved.

If your bathroom scale is off, you may be annoyed. If your oven runs a little hot, your cookies may suffer. If your directions are wrong, you may lose ten minutes. But if a property corner is wrong, the consequences can last for years. A fence may be built in the wrong place. A driveway may cross land it should not cross. A building may violate a setback. Timber may be cut across a line. A land sale may include less acreage than someone expected. In those situations, precision is not enough.

That does not mean every survey is perfect or that every boundary question is simple. Land records can be old. Descriptions can be vague. Monuments can be missing. Fences can move. Roads can change. Rivers and bayous can make things even more interesting.

Around here, the land has a long memory, but it does not always speak clearly. The surveyor’s job is to listen to all of it.

The numbers matter. The equipment matters. The measurements matter. But they are only part of the story. They are tools. They help us document, communicate, and preserve the evidence we find.

Good surveying requires both precision and accuracy. We need careful measurements, and we need those measurements connected to the right evidence. Precision helps us communicate the location of a boundary.

Accuracy comes from knowing what boundary we are supposed to be communicating in the first place.

A good modern survey should not have to choose between the two. But it is important to understand that without accuracy, all of those fancy numbers are just for show.

So, the next time you hear someone talk about accuracy and precision, think about that bathroom scale. Think about bad directions. Think about a tight group of shots on the wrong side of the target.

Being consistent is good. Being correct is better. Being both is the goal.

When it Matters, Make it Marling!