Standardized Measurement and Assessment
(For the concept map that goes with this chapter,
When we measure, we attempt to identify the dimensions, quantity, capacity, or degree of
is formally defined as the act of measuring by assigning symbols or
numbers to something according to a specific set of rules.
Measurement can be categorized by the type of information that is communicated by the
symbols or numbers assigned to the variables of interest. In particular, there are four
levels or types of information are discussed next in the chapter. They are called the four
"scales of measurement."
Scales of Measurement
This is a nonquantitative measurement scale.
It is used to categorize, label, classify, name, or identify variables. It classifies
groups or types.
Numbers can be used to label the categories of a nominal variable but the
numbers serve only as markers, not as indicators of amount or quantity (e.g., if
you wanted to, you could mark the categories of the variable called "gender" with
1=female and 2=male).
Some examples of nominal level variables are the country you were born in,
college major, personality type, experimental group (e.g., experimental group or
This level of measurement enables one to make ordinal judgments (i.e., judgments
about rank order
Any variable where the levels can be ranked (but you don't know if the distance
between the levels is the same) is an ordinal variable.
Some examples are order of finish position in a marathon, billboard top 40, rank
This scale or level of measurement has the characteristics of rank order and equal
(i.e., the distance between adjacent points is the same).
It does not possess an absolute zero point.
Some examples are Celsius temperature, Fahrenheit temperature, IQ scores.
Here is the idea of the lack of a true zero point: zero degrees Celsius does not
mean no temperature at all; in a Fahrenheit scale, it is equal to the freezing point
or 32 degrees. Zero degrees in these scales does not mean zero or no temperature.