Week 4 - Reliability Flashcards
What does quantitative research necessitates?
Measurement, whether that be physical or abstract things
What is the assumption with quantitative research?
Everything we want to measure has a true value, or a true score
What is the goal or quantitative research?
Measurement will give us a pure score
What is the reality of quantitative research?
Measurement always includes some amount of “random noise”.
Measured score = true score + noise
What does reliable mean in a quantitative study?
Tools used for measurement must be consistent and accurate (precise and unbiased)
What does valid mean in quantitative research?
Descriptions, relations and explanations (causation) must be truthful
What does reliability equal?
Consistency
What are the three broad types of consistency in research?
Consistency:
Over time (test-retest reliability)
Across items (internal consistency)
Consistency across researchers (inter- rater reliability)
What is consistency measured by?
Variability
What is an inverse relationship?
Research should indicate an inverse relationship if the two variables are related. Therefore:
High variability = low reliability
Low variability = high reliability
A reliable measure is also a what?
Valid measure
Can any measure that is not consistent provide trustworthy evidence?
No
Is a measure that is reliable always valid?
Not necessarily no.
What are the two reasons for which variability occurs?
- Causal relationship between an IV and DV variable (effect)
- when a IV changes, a DV also changes
- Variability due to random factors (noise)
- unknown (possibly unknowable) factors affect DV
Careful research designs are needed to separate effect from noise
Noise can be reduced, but not eliminated
What is variability due to noise called?
Error
What does error mean in research design and statistics error?
Means variability whose cause is unknown, which does not mean MISTAKE.
What might short term change in results indicate?
Problems with reliability (and therefore validity).
Caution: some measures are inherently variable (e.g reaction time)
Might need multiple measurements
What might long term change (with short term stability) indicate in research?
More likely to reflect a real effect. More likely to reflect real changes in variable, not merely error.
What are two things body temperature can measure with an illness.
To indicate development of illness following exposure
Track progression of illness during sickness.
But the measurement device must be reliable.
What is test retest reliability?
Relating a measure on two occasions then calculating the correlation between two occasions. High test retest reliability results in a strong positive correlation.
What is internal consistency?
Consistency of responses across test items
What do assessments of psychological, behavioural and health related constructs often use?
Questionnaires.