Measurement, reliability + Validity Flashcards Preview

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Flashcards in Measurement, reliability + Validity Deck (23)
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Why is it important for psychologist to quantify everything?

- is a defining principle of science = measurement
-- can be objectively obtained
-- publicly available
-- potentially checkable by others


What are the requirements for measurements?

- reliable = can be reproduced
- valid = actually measuring what we think it is measuring


What are the different levels of measurements?

1. Nominal
2. Ordinal
3. Interval
4. Ratio


Describe nominal level of measurement

- categorical. frq data
- when numbers are used as names (eg footballer numbers)
- All you can do is count how often each number occurs


Describe ordinal level of measurement

- numbers used as ranks
eg: order of finishing a race


Describe interval level of measurement

-scale with equal interval between points on a scale
- no true zero point
eg: IQ


Describe ration: level of measurement

- measurements made on a scale with equal interval between points on the scale
- scale has TRUE 0 point
Eg: reaction time, error scores


What is reliability?

- does it give consistent/ reproducible results?


Error in reliability may be due to....?

- natural phenomena variation
--> within/ between individuals
- imprecision in defining + measuring psychological constructs
--> what exactly is aggression?


What are different measures of reliability?

1. Test-retest: time to time
2. Alternate forms: version to version
3. Split-half: item to item
4. Inter-scorer: person to person


What factors affect reliability?

- phenomena itself
--> trait vs state?
- Precision of measurements
- Sample size
- Variability in performance
--> High > low
- Format of test:
--> MCQ of 5Q = 25% correct by chance > than ....
--> True/ False = 50% correct by chance


What is the replication crisis?

- many well-known findings aren't that reliable
--> small sample size
--> Exact replication are rare
--> "file drawer problem"


What is the "file drawer problem"?

- hard to get replication failures published


What are some solution to the replication crisis?

- replications
- Metal-analysis
- Converging operations = tackling problem with different methods, by different research groups


What are the 10 frq cited findings that have failed to replicate as found by Jarrett in 2016?

1. power-posing
2. Smiling = happier
3. exposure to age related words = slower walk (x social priming)
4. Babies are born with the power to imitate adults


What did Nosek et al in 2015 find when he replicated 100 experimental + correlational studies?

1. og 97% significant results (p<0.5)
2. replication = 36% significant results
3. 47% replication significance size similar to og
= 68% studies w/ statistically significant effects


What does validity mean?

- are you measuring what you think you are measuring?
- a measure can be reliable without being valid (since you can replicate it i guess)


What link did Paul broca poorly attempt to make?

- anthropometric measurements + intelligence
- eg brain size saying there was a 14% difference between F +M but no regards for age/ body size given


What did Gall + Spurzheim which was scientific + testable but had poor vlaidilty?

- different parts of brain responsible for different functions
- highly developed regions = larger = reflected by bumps on skull
- craniometry measuring tool


What are the different types of validity?

1. Face
- intuitively looks plausible
2. Content
- relevant material covered??
3. Criterion
- predictive or concurrent
4. Construct
- does performance correlate well with known measures of the phenomena?
5. Ecological/ external
- relevance to rl


What does the predictive or concurrent criterion mean?

p: Does performance on test correlate w/ later performance?
C: does performance on my test correlate w/ other tests of current performance?


What factors affect the validity of experiments?

- good or bad experimental design
-method of difference: only one thing needs to differ between comparing conditions


What factors affect validity of tests?

- Norms + clear experimental standardisation