Midterm 1 Flashcards
Research variables
Independent: typically manipulated
Dependent: always measured
Control variable
Experiment (3 steps)
Hypothesis
Experimental manipulation (independent variable)
Interesting outcome
Categorical
Levels are categories
Ordinal
Quantitative variable
Numerals represent a rank order, but distance is not equal
Interval
Quantitative variable
Numerals have an equal distance, but no real zero
Ratio
Quantitative variable
Numerals have an equal distance but there is a real zero
Reliability
Consistency of results over time
Less spread: more reliable
How well we’ve measured something in a technical sense irrespective of what it is we’re measuring
Internal reliability
Internally consistent
Correlate with itself
Test-retest
Same results over time
Correlate with itself on 2 occasions
Inter-rater
Two or more observers agree (scores correlate)
Validity (definition)
We have properly captured the construct of interest
Link between validity and reliability
For a measure to be valid, it has to be reliable
For a measure to be reliable, it doesn’t have to be valid
Assessing validity (4 questions to ask yourself)
- Is it possible you’re measuring something else
- Are you measuring some part innacurently
- Are you measuring all important aspects
- Are you measuring it well enough to suit your intended argument
Internal validity
Is there a better alternative explanantion?
Construct validity
Capture the right thing
Statistical validity
How big is the effect
External validity
Representative sample
Face validity
Does it seem to be valid
Content validity
Capture all the aspects
Criterion validity
Relate to a concrete outcome
Convergent validity
Relate to other things it should
Discriminant validity
Not relate to other things it shouldn’t
Good design
Captured construct well
Good number of items
Good answers
Order effects
Response sets
Faking