Chapter 1 - Variables And Measurement Scales (Book Notes) Flashcards
What is measurement?
Refers to the method or the tool that you use to make your observations.
Examples:
* A question in a survey
* A behavioural observation
* A brain scan
Finding some way of assigning numbers, or labels, or some other kind of well-defined descriptions, to “stuff.”
Data collection can be thought of as a kind of measurement.
Psychological measurement examples:
* My AGE is 33 years.
* I do not LIKE ANCHOVIES.
* My CHROMOSOMAL GENDER is male.
* My SELF-IDENTIFIED GENDER is male.
* In the short list above, the CAPITALIZED part is “the thing to be measured”, and the lowercase part is “the measurement itself.”
What is operationalisation?
The process by which we take a meaningful but somewhat vague concept and turn it into a precise measurement - we make it operational.
Refers to the logical connection between the measure and the theoretical construct, or to the process by which we try to derive a measure from a theoretical construct.
You’ll need to:
* Be precise about what you are trying to measure (age since time of birth or time since conception).
* Determine what method you will use to measure it (self-report, ask a parent, use official record).
* Define the set of allowable values that the measurement can take. These values don’t always have to be numerical, though they often are (do we want age in years, years and months, days, or hours).
There’s no “one, true way” to do it.
Needs to be thought through on a case-by-case basis.
What is a theoretical construct?
The thing that you’re trying to take a measurement of, like “age”, “gender” or an “opinion”.
A theoretical construct can’t be directly observed, and often they’re actually a bit vague.
What is a variable?
What we end up with when we apply our measure to something in the world. That is, variables are the actual “data” that we end up with in our data sets.
Scales of measurement
A very useful concept for distinguishing between different types of variables.
