Welcome to the Making Molehills out of Mountains University (MMoM U) Market Research Data Analysis 101 or MARDA 1 as we like to call it in the halls of academia. Today we discuss the four different types of scales used in measuring behavior. Open your books and let’s get started…
The four scales, in order of ascending power are:
Nominal Scale
Nominal is derived from the Latin nominalis meaning “pertaining to names”. But, seriously, who cares? That tells us nothing except how much academics love showing off. The Nominal Scale is the lowest measurement and is used to categorize data without order. For your market research data analysis exercise a typical nominal scale is derived from simple Yes/No questions.
How the nominal scale (and all these scales) is used statistically is for the next lecture. For now, just know the behavior measured has no order and no distance between data points. It is simply “You like? Yes or no?”
Ordinal Scale
From the Latin ordinalis, meaning “showing order”… Enough of that. An Ordinal Scale is simply a ranking. Rate your preference from 1 to 5. Careful! There’s no distance measurement between each point. A person may like sample A a lot, sample B a little, and C not at all and you would never know. Here we have gross order only, learning that the subject likes A best, then B, then C. Determining relative positional preference is a matter for the next scale.
Interval
Ah, the Interval Scale. It’s the standard scale in market research data analysis. Here is the 7 point scale from Dissatisfied to Satisfied, from Would Never Shop Again to Would Always Shop, etc. The key element in an Interval Scale is the assumption that data points are equidistant. I realize savvy market analysts might say, “Hold on Professor. What about logarithmic metrics where the points are not equidistant?” To which I say, “Correct! but the distances are strictly defined depending on the metric used, so don’t get ahead of yourself. This is MARDA 101.”
For now, understand that with the Interval Scale, we can interpret the difference between orders of preference. Now we can glean that Subject 1 Loves A, Somewhat Likes B and Sorta Kinda Doesn’t Like C.
Subject 2 Somewhat Likes A , Sorta Kinda Doesn’t Like B and Hates C. Both subjects ranked the samples A, B, & C on an Ordinal Scale but for very different reasons as discovered by using the Interval Scale. Got it? Good.
Moving on.
Ratio
Similar to the Interval Scale it’s not often used in social research. Like Interval, it has equal units but it’s defining characteristic is the true zero point. Ratio, at its simplest, is a measurement of length. Even though you cannot measure 0 length; a negative length is impossible, hence, the true zero point.
To sum up, I leave you with the the chart below, indicating various measures for each scale.

Difference

Direction of Difference

Amount of Difference

Absolute Zero

Nominal 
X 



Ordinal 
X 
X 


Interval 
X 
X 
X 

Ratio 
X 
X 
X 
X 