Variables
Scale
To measure a variable, we can use one item or a range of items (that form a scale).
For example, to measure the variable “depression”, we can create a scale for depression that consist of three items (i.e. three survey questions).
Note: This scale is quite different from fish scales :)
For example, to measure the variable “depression”, we can create a scale for depression that consist of three items (i.e. three survey questions).
Note: This scale is quite different from fish scales :)
Some scales are better than others
The more these items (within a scale) are related to each other, the higher the reliability of this scale in measuring the variable “depression”.
Such a reliability can be computed by softwares to give us what is known as an alpha-value. We will talk about this later in the course.
The simpler way in research is to use an existing questionnaire, or an existing scale from a questionnaire. We would usually choose one that we can trust, i.e. that has good validity and reliability.
Such a reliability can be computed by softwares to give us what is known as an alpha-value. We will talk about this later in the course.
The simpler way in research is to use an existing questionnaire, or an existing scale from a questionnaire. We would usually choose one that we can trust, i.e. that has good validity and reliability.