Midterm #1 - Measurement and Variables Flashcards
conceptual definitions
- help us understand what a construct means but don’t tell us how to quantify the construct
variables
- actual representation of the construct
nominal (data)
- data recognized with no inherent order
ordinal (data)
- data categorized and ranked
continuous (data)
- interval: categorized, ranked, and evenly spaced
- ratio: categorized, ranked, evenly spaced, natural zero
construct
- concept
- can’t be directly observed
- abstract
operational definition
- specific and concrete
- represent a construct
ways to measure behaviour
- observe it: naturalistic, get records, unobtrusive
- ask about it: self-report, informant
psychometrics
- scientific discipline concerned with measurement
condition a (data entry)
- baseline
condition b (data entry)
- intervention
quasi-independent variable
- treated as IV but not manipulated
quasi-experimental designs
- researcher can’t manipulate IV or use random design
self-report
- directly ask participants when observation not possible
- cheap and easy but could have bias
behavioural trace
- relies on evidence left behind by a person who isn’t present
- drawing inferences
behavioural observation
- relies directly on seeing or observing behaviour
- better if participants don’t know
behavioural choices
- involves participants making a purposeful selection from several options
random error
- variation from the measure’s true score due to unsystematic or chance factors
- measured with stats
bias/systematic error
- varies systematically or consistently pushes scores higher/lower in a way that leads to inaccurate/misleading conclusions
standardization
- environmental situation same for everyone
observer/scorer bias
- misinterpreting an observation based on the researcher’s existing belief, previous experiences, or expectations
ceiling effect
- occurs when upper boundary of a measurement tool is set too low
floor effect
- occurs when lower boundary of a measurement is set too high
reliability
- stability/consistency of a measure
validity
- the degree to which a tool measures what is claims to measure
if you fail to establish ______ you can’t have _______
- reliability
- validity
population
- entire group of interest in a research study
- sample drawn
sample
- a subset of the population
- where data is collected
representative sample
- a sample with specific features that characterize the population of interest
probability sampling
- everyone in a population has an equal chance to participate
simple random sampling
- subset of individuals is randomly selected from population members
stratified random sampling
- dividing population into strata or subpopulations
- use simple random sampling to select participants
cluster random sampling
- dividing the total population into groups
- use simple random sampling to select which clusters participate
non-probability sampling
- everyone in the population doesn’t have an equal chance of being sampled
convenience sampling
- nonrandom selections of participants who are readily available to the researcher to serve as the sample
quota sampling
- freely choosing any participant as long as they help meet predetermined targets for sample’s characteristics
purpose sampling
- sample chosen based on who researcher thinks is the most qualified
snowball sampling
- existing study participants recruit future participants from among their acquaintances
nonresponse bias
- a potential systematic difference between those who refuse to participate and those who don’t
the volunteer subject problem
- likely a bias with only volunteers