Lecture 4: Sampling and Measurement Flashcards
What is population?
entire group of people of interest
What is a sample?
smaller group of people who complete study procedures
What are representative samples?
sample should be similar enough to the population to make generalizable conclusions
How can you have more representative samples?
- sampling technique
- larger samples
- breadth of recruitment
What are different sampling techniques?
probability sampling and non-probability sampling
What is probability sampling?
all members of the population have a known probability (chance) of being selected for the sample
- more likely to result in a representative sample
What is non-probability sampling?
there is no real effort to ensure that sample accurately represents population
- less likely to result in representative sample on their own
What are the general approaches to measurement?
- self-report measures
- behavioural measures
- physiological measures
How do you choose a measure?
- nature of operalization & research question/hypothesis
- cost
- quality (reliability, validity, reactivity)
What is reliability?
how consistently a measure measures a particular variable
What are the different types of reliability?
- internal consistency
- test-retest reliability
- inter-rater reliability
What is internal consistency?
how consistent is the measure across items measuring the same concept
What is test-retest reliability?
how consistent is the measure across time points
What is inter-rater reliability?
how consistent is the measure across different raters
What is validity?
how well a measure measures the variable it is intended to measure
What are the different indicators of construct validity?
- face validity
- content validity
- predictive validity
- concurrent validity
- convergent validity
- discriminant validity
What is face validity?
measure appears to measure the construct of interest
What is content validity?
measure captures necessary aspects of construct, nothing more
What is predictive validity?
extent to which scores on the measure predict related criteria measured later
What is concurrent validity?
extent to which scores on the measure are related to another relevant variable measured at the same time
What is convergent validity?
extent to which scores on the measure are related to other measures of the same/similar constructs
What is discriminant validity?
demonstration of scores on the measure being unrelated to measures that are not conceptually related to the construct
What is reactivity?
the degree to which participants’ behaviours/responses change as a result of measurement
What are issues of reactivity in self-reports?
- participant may deny being stressed in the interest of appearing “tough” or “strong”
- participant may also exaggerate their stress reaction if they thought they may have something to gain from it
How do you minimize issues of reactivity in self-reports?
- remind participants to be as honest as possible
- anonymous data collection
What are issues of reactivity in behavioural measures?
- participant may be more nervous knowing they’re being observed so might display more stress behaviours than usual
- participant may hide stress
How do you minimize issues of reactivity in behavioural measures?
- give time under observation
- use naturalistic observation or deception
What issues of reactivity in physiological measures?
- physiological reactions may be exaggerated simply by them being measured
How do you minimize issues of reactivity in physiological measures?
have a longer baseline where participant is connect to get comfortable being attached to machines
