Measure Quality Flashcards
What are the 2 things psychologists need to consider about the quality of their measurements?
Reliability/Precision = exactness (consistency)
Validity/Accuracy = correctness (truthfulness)
What is precision?
Exactness (consistency)
What is accuracy?
Correctness (truthfulness)
What is Reliability?
Precision
- The extent to which our measure would provide the same results under the same conditions
What is Validity?
Accuracy
- The extent to which it is measuring the construct we are interested in
What is Validity?
Accuracy
- The extent to which it is measuring the construct we are interested in
Simply = Whether the results really do represent what they are supposed to measure
What does it mean when our measures have high validity and high reliability?
Our measures are precise and accurate
What does it mean when our measures have high validity and low reliability?
Our measures are precise but not accurate
What does it mean when our measures have low validity and high reliability?
Our measures are not precise but are accurate
What does it mean when our measures have low validity and low reliability?
Our measures are neither precise or accurate
We want to investigate the relationship between head size and intelligence
Is head size a …?
1) Reliable measure
2) Valid measure
1) Reliable measure = Yes. If you were to measure the head again with measuring tape it would be the same size
2) Valid measure = No. Because the head size is not actually measuring intelligence
What are the 2 forms of reliability?
1) Temporal consistency
2) Internal consistency
What is temporal consistency?
Assumes that there is no substantial change in construct being measured between 2 occasions
Simply= If we test our instrument twice, with a time interval between the two tests, there will be no change in results
What is internal consistency?
The extent to which items within an instrument measure various aspects of some characteristics
Simply = How well does an instrument actually measure what you want it to measure?
What is the Test-Retest Reliability?
It measures fluctuations from one time to another
We administer the same test/measurement twice over a period of time to a group of individuals and see if we still get the same results
Important for constructs which we expect to be stable (e.g. personality type)
What is one limitation of the Test-Retest Reliability?
Order effects
What is Inter-Rater Reliability?
It measures fluctuations between observers
It evaluates the extent to which different judges agree in their assessment decisions (to assess the reliability of answers produced by different items on a test)
What is Parallel Forms Reliability?
Measures reliability by using different versions of the assessment tool/test to the same group of participants
Different versions of a test can be useful to help eliminate memory effects as the questions are different
List one advantage and one disadvantage of Parallel Forms Reliability?
Pro = Different versions of a test can be useful to help eliminate memory effects as the questions are different
Con = Order effects
What is internal consistency (reliability)?
Measures the degree of homogeneity among the items on a test, such that they are consistent with one another and measuring the same thing
e.g. all items in a questionnaire are measuring
the same construct
What is one disadvantage of internal consistency (reliability)?
Order effects
What are the 4 forms of reliability?
1) Test-retest reliability
2) Inter-rater reliability
3) Parallel forms
4) Internal consistency
What are the 4 forms of validity?
1) Face validity
2) Content validity
3) Criterion validity
4) Construct validity
What is face validity?
Evaluates whether a test appears to measure what it’s supposed to measure (is it relevant to what it’s assessing?)
Does it look like a good test?
e.g. do the questions in the RM exam reflect the RM knowledge students should have learnt?
