12 Causal Research and Internal Validity Flashcards
what is descriptive research?
gather info about phenomena
what is causal research?
what is cause of illness or other phenomenon–>provides empirical evidence, basis to formulate or justify treatment
criteria for causality?
1) antecedence of cause to effect
2) co-variation of cause and effect
3) elimination of rival cause explanations
what are threats to internal validity?
history, maturation, testing, instrumentation, regression to mean, selection, mortality,
what is history threat?
events between pre and post test not part of treatment
what is maturation threat?
time-dependent internal process
what is testing threat?
repetition of / familiarity with test procedure change result
how can testing increase or decrease performance?
more familiar = better IQ testing, but repetition can make bored or tired
what is instrumentation threat?
instrument changes between measurement
what is regression to mean?
from unreliability of test measures (first measure may be abnormally high due to error)
how to prevent regression to mean?
increase number of tests
what is selection threat?
groups differ at outset, because may select for people who are more likely to respond, or non-matched assignments
what is mortality threat?
dropouts more in one group than other, dropouts differ from ppl who stay, replacements differ
with people, need be careful of ___ effect
placebo
how to control for placebo effect?
no treatment vs. placebo vs. treatment (measure size of effect)
