Precision vs Accuracy

[Deleted member 107796]

Albeit a simple and basic concept, is there anyone out there that does not know the difference between precision and accuracy?

Using a target as an example, precision has to do with how tightly it groups.
Accuracy has to do with how close to the bullseye the group is.

 

[cohunt]

definition of precision is "being both exact and accurate"
definition of accuracy is "being correct or precise"

 

[Deleted member 107796]

definition of precision is "being both exact and accurate"
definition of accuracy is "being correct or precise"

With these definitions, you have to add the definitions of "correct" and "exact" which is fine but is a bit more convoluted than what I was trying to present. When you think of a shot grouping, here are examples:

The reason why the second picture is high accuracy is that the center of the grouping is at bullseye. I brought this post up since they are truly, two different variables. I spent most of my career doing statistical analysis in the engineering field and I always liked how one of my mentors used a target to characterize the difference. cheers y'all

 

[catamountsierra]

With these definitions, you have to add the definitions of "correct" and "exact" which is fine but is a bit more convoluted than what I was trying to present. When you think of a shot grouping, here are examples:
View attachment 118989 The reason why the second picture is high accuracy is that the center of the grouping is at bullseye. I brought this post up since they are truly, two different variables. I spent most of my career doing statistical analysis in the engineering field and I always liked how one of my mentors used a target to characterize the difference. cheers y'all

This is exactly how I describe it. I have work as a geologist or hydrologist for my whole career. Trying to explain this to students during grad school was a often an exercise in patience. I'll go with precision any day because if something is precise it can (most likely) be calibrated (dialing elevation on your scope) to also be accurate or the bias can be accommodated (holdoff or Kentucky windage). If something is not precise, it just comes down to luck as to whether or not you hit the target, which if it is accurate, but not precise, you may do some percentage of the time dependent on the degree of precision.

 

[RiverSink]

Precision is the gun. Accuracy is the one pulling the trigger. Or that's how I always looked at it.

 

[Deleted member 107796]

Precision is the gun. Accuracy is the one pulling the trigger. Or that's how I always looked at it.

If your load or scope isn't dialed in or many other conditions, it won't be accurate, regardless of who is shooting.

 

[RiverSink]

I thought that went without saying, but thanks for pointing it out for those that didn't know.

 

[Missouri57]

I would have thought it was just the opposite. Without mechanical accuracy, (rifle-scope combo), you cannot be Precise, (ie placing the shot exactly where you want it.)
You can have accuracy without precision but not the other way around.

 

[Deleted member 107796]

I would have thought it was just the opposite. Without mechanical accuracy, (rifle-scope combo), you cannot be Precise, (ie placing the shot exactly where you want it.)
You can have accuracy without precision but not the other way around.

I'm glad you added this because my earlier post was a bit confusing. The left image above, is an example of hi precision and lo accuracy. Let's leave out the gun and shooter variables and just look at the grouping, say, the gun is in a mechanical vise and we are shooting loads that are exactly the same. Do the examples of accuracy and precision, above, make sense for this condition? The grouping defines the accuracy (how close is the group about bullseye) and precision (how tight the group is) of the system. When you add the shooter variables, then your grouping will still be defined this way. In other words, precision and accuracy are only applied to the grouping.
This addition of the shooter is exactly why an addition of a few rounds (5 shot test group vs 3) will add more real statistical info to how you are shooting, since we all pull to some extent when we are holding the rifle. IMO, unless mechanically held, ladder tests need to have more than 4 shots per charge. 5 is better.

 

[Sflutes]

I agree that precision is what the equipment and the power components are capable of, and accuracy is what the whole package is capable of, operator included. But, there are degrees of everything, and it is an impediment to a friendly conversation to make too big of a deal about definitions. Most of the people I know talk about how accurate their guns are, and I don't embarrass them by making a point of correcting their assertions. In fact, I usually even talk in the common terms, even though I know they are technically wrong. It's just good manners, in the circles I travel in.

 

[Buxndiverdux]

 

[Greyfox]

Unless asked, I'll avoid a lecture for the reasons mentioned. Less then 12 posts in on this thread, and there is already some debate brewing. A picture is worth a thousand words...If the "why", as opposed to the 'what" is brought into the picture it's a much longer discussion.

 

[Deleted member 107796]

Unless asked, I'll avoid a lecture for the reasons mentioned. Less then 12 posts in on this thread, and there is already some debate brewing. A picture is worth a thousand words...If the "why", as opposed to the 'what" is brought into the picture it's a much longer discussion.
View attachment 124832

I'd disagree only because within these few posts we've actually reached complete agreement vs debate! Precision and accuracy are applied to define the grouping. Your images reinforce mine and the group test conditions, e.g., shooter held or mechanically held, bullet details, barrel profile, etc., are the "why" you mention. In the end, the resulting group's precision and accuracy is what being defined. The rest are test conditions.
As to being cordial and friendly during conversations, I think you can break down words without being negative or condescending. It's actually fun when you do it honestly and in search of truth.

 

[Greyfox]

Points well taken......"debate" was probably the wrong choice of wording .......thanks