nonexperimental and quasiexperimental Flashcards
quasi vs non experimental
quasi: 1 variable w/ 2 levels, uses preexisting group differences
non-experimental: measures 1 variable for 2 groups - compares scores between the 2
pre-existing independent variable
when the subject characteristic is your independent variable, cannot randomly assign participants to groups poses problems for interpreting results
trangenic mouse
investigate the independent variable, artificially constructed DNA incorporated into genome
non equivalent group design
groups are not equivalent bc of individual differences, assignment bias=> threat to internal validity, between-subjects design
differential research design
compare 2 groups of participants as they are, formed by their pre-existing variable, nonequivalent groups, no manipulation or intervention of the groups
posttest-only nonequivalent control group design (non)
start with 2 pre-existing group, 1 group w/ treatment and one without, compare both groups after experience, no ctrl for equivalence
pretest-posttest non-equivalent control group design (quasi)
between-group but tested pre and post, pretest offers a control
time-related design
prepost design, no control group, comparing before and after,
threats to internal validity= history, maturation,instrumentation, order
Time series desin
take multiple measurements before and after treatment, shows any trends that may already exist in data before treatment starts
developmental research
study change as a function of age, longitudal design(within subject), cross-sectional(between-subject)
cross-sectional design
pros: all individuals studied at the same time
cons: different individuals at each age group, cohort effects(differences in age groups due to unique charactersitics)
longitudal
pros compare between differentaes therefore done in the same individuals
cons: very long, the same individuals are studied over time-high attrition, takes a very long time
