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Measurement

Measurement

Author: Paul Hannan
Description:

Recognize key methods of measurement.

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Tutorial

Source: Intro Music by Mark Hannan; Public Domain Images from www.cliker.com; Public Domain

Video Transcription

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[MUSIC PLAYING] Welcome this episode of Sociology Studies of Society. Today's lesson is on measurement. As always, don't be afraid to pause, stop, rewind, or even fast forward to make sure get the most out of this tutorial.

[MUSIC PLAYING]

So today we're looking at measurement. And measurement in sociological terms can be just simply measuring something with a ruler, but it can also be some other things. So I'm going to try to explain in this lesson a little more about what measurement can be for sociologists.

Now why does sociologists care about measurement? Well they're trying to really find a way to break down a really-complex world into smaller parts. And the first way they do that is they try to establish a concept. And a concept is just a simplified representation of something from the world. So they're trying to simplify something into an easier way to process and understand it and start to categorize things.

So a good example of a concept could be social class. So down below there, you know we have a wealthy woman and a not so wealthy man. We don't know if they're necessarily rich or poor or upper middle class and middle class, but either way social class is that concept. And we can start to define this really-complex world and try to put things into different categories.

Now a variable is something whose values can change from case to case. And there are really two different types of changes. There's independent variables and dependent variables.

So the independent variable is the cause of the change. The dependent variable is what is being measured. And that's the effect of the change. So what is the result of that change in the independent variable?

Now when you look at measurement, it really, I guess technically, means determine the value of a variable in a specific case. That definition is really just a fancy way of saying, is you're trying to figure out what something is. So you need to, you know you need to turn whatever you're looking at into something else. So you're determining the value. You're figuring out what something is of a variable in a specific case.

So, measurement of height, I'm determining the value, in this case my height, how many how tall am. I am six feet and one inch tall, and in a specific case, so today, August 15th. Or when I was 19 I was a certain height.

Now, when you're looking at measurement, there's two different things to consider. There's reliability and validity. Now these two things are really interconnected, and they can be a little bit hard to understand. So after I explain these two definitions I'll show you some images that I think will help you understand them.

But reliability is just the consistency of measurement. So how consistently can you measure something? The validity is how much does this measurement mean what you actually want it to measure.

Now height's a pretty easy one to measure and be both reliable and valid because it's pretty consistent, as long as your ruler is set up right. It's pretty easy to measure that you're going to get the same consistency in those measurements. And, if you're trying to measure height, it's a pretty valid measurement pretty easily cause that's exact what you're measuring.

Now let's say you're using height, but what you're really trying to measure is how good people are at basketball. The reliability might still be good because you're consistently measuring people's height correctly. But the validity might be off because measuring someone's height doesn't actually measure the concept you're looking at, which is how good they are basketball.

Here are those images I promised. And there are four different ways I kind of break them down. And you can think of it like aiming at a target. And, if something's in the center of the target, that's really what you want to find. So we have, first thing on the first target on the far left there is reliable but not valid. So you see all those bullets are all clustered together. That means that the measurement is probably pretty accurate. You're measuring something, but it's not exactly the bull's eye. It's not exactly the concept you want to want to measure.

Now the next target you can see the answers are all over the place. Right, so this means that the measurement is probably not very reliable. And it might be valid, but you can't really tell because the measurement is not that reliable. So it's hard to-- and you can't judge when you're not getting consistent measurement.

Now this one the answers are even farther spread out. So it's not reliable or valid probably. It's just a mess. What you're really looking for when you're measuring is something that is reliable and valid. So you are getting-- you are measuring what you want to measure. And you're measuring what you want to measure effectively. So it's both valid, you're measuring what you want to measure, and you're measuring it correctly, which is reliable.

So today's takeaway message, a concept is just a simplified representation of something from the world. And a variable is something whose values can be changed from case to case. You can think of these variables as either independent or dependent. Independent variables are the cause of the change, and dependent variables are the effect of the change.

Then we have measurement. Measurement is determining the value of a variable in a specific case. And these measurements should be both reliable and valid. So, if it's reliable, it's a consistent measurement. And, if it's valid, the measurement measures exactly what you want it to.

That's it for this lesson. Good work and hopefully you'll be seeing me on your screen. Again soon. Pece.

Terms to Know
Concept

A simplified, working representation of the social world; i.e. "class" or "family."

Dependent Variable

The "effect" or the outcome of the change in the independent variable.

Independent Variable

The "cause" driving the change in the dependent variable.

Measurement

The process of determining the value of a variable.

Reliability

Consistency in the valuation of a variable.

Validity

Actually measuring the data the you set out to capture.

Variable

A characteristic such as age, class, income, education, ect.. that varies throughout the population as a whole.