Week 1 - Chapter 14: Measurement and scales Flashcards
Measurement is a three part process consisting of the following steps:
Selecting observable empirical events
Developing a set of mapping rules, which is a scheme for assigning numbers or symbols to represent aspects fo the event being measured
Applying the mapping rules to each observation of that event
What are the 4 characteristics of mapping rules?
Classification
Order
Distance
Origin
Classification
Where numbers are used to group or sort responses and an order does not exist
Order
Where numbers are ordered and where transitivity is applicable
Distance
Where the differences between numbers are ordered
The difference between any pair of numbers is greater than, less than, or equal to the difference between any other pair of numbers
Origin
Where the number series has a unique pricing indicated by the number zero
Nominal
Where the numbers indicate categories, and where the order is not meaningful.
For example, the category man is 1, the category woman is 2
Ordinal
Where the order in the numbers is important, intervals between numbers are not fixed, and where calculations are possible
For example, clothing sizes
Interval
Where the order in the numbers is important, intervals between numbers is fixed, where there is an arbitrary zero point, and basic calculations can be done
For example, temperature
Ratio
Where the order win the numbers is important, intervals between numbers are fixed where there is a fixed meaningful zero point, and all calculations are possible.
For example, length in centimetres
What are the 4 sources of error?
The participant
Situational factors
The measurer
The data collection instrument
What are the two major criteria for evaluating the soundness of a measurement tool?
Validity
Reliability
Internal validity
The ability of a research instrument to measure what you want to measure
External validity
The extent to which findings can meaningfully be generalised to other settings, situations, or persons
Content validity
The extent to which the measuring instrument provides adequate coverage of the concept being studied
