class 8-9 Flashcards
research study design
blueprint or detailed plan for conducting a study
what is a design
-addresses the research problem in an appropriate way
-determines the degree of bias and/or control
-guides the researcher in planning and implementing a study
experimental (interventional) design
-experimental
-quasi-experimental
non-experimental (observational) design
-correlational
-descriptive
-comparative
design: time dimension
cross-sectional design
data collected at one point in time
design: time dimension
prospective design
data collected at one point and then again at future point(s)
may be longitudinal
design: time dimension
retrospective design
data collected and compared against previously collected data or in relation to something that occurred in the past
causality - design concepts
A causes B
relies on temporality being able to determine the independent variable occured/changed before the outcome
multicausality - design concepts
same as causality but A,C,D… causes B
manipulation - design concepts
-intentionally controlling/altering a condition or treatment (independent variable)
-must be consistent
bias - design concepts
distorts findings away from the truth
-researchers must attempt to eliminate or substantially reduce randomness & blinding
control - design concepts
keeping study conditions constant
-reduce bias
-improves accuracy of findings
-impacts generalizability
control can be applied to:
sample
setting
treatment/intervention
measurement
extraneous variables
design validity
-measure of truth or accuracy of a study
statistical conclusion validity
are the conclusions drawn from statistical analyses an accurate reflection of the real world
type 1 error statistical conclusion validity
incorrectly concluding that a difference or relationship exists
type 2 error statistical conclusion validity
incorrectly concluding that a difference or relationship does not exist
construct validity
-congruency between operational definitions and conceptual definitions
-to what degree do the instruments sued actually measure the variable being studied
threats to construct validity
-conceptual and/or operational definitions not clearly defined
-instrument selection
internal validity
-is there another reasonable explanation for the study findings
-are the findings a true reflection of reality or the result of extraneous variables
history - threats to internal validity
external events impacting subjects & data collected
maturation - threats to internal validity
-changes within subjects over time that influence study findings
testing - threats to internal validity
-effects of taking pre-test on post-test
instrumentation - threats to internal validity
variables measured improperly
subject selection - threats to internal validity
-participants or groups differ from the population
mortality - threats to internal validity
participants/subjects dropping out
diffusion of treatment (imitation) - threats to internal validity
control group has access to treatment
external validity
-can the findings be applied to individuals/groups or contexts outside the study (generalizability)
selection bias - threats to external validity
limited generalizability to other populations (sample is not representative)
reactivity - threats to external validity
subjects alter their responses due to being studied (i.e. trying to make their answer what the researcher is looking for vs what they want to say)
measurement effects - threats to external validity
testing effects
observer bias
problems with study designs
-inappropriate for purpose and/or framework
-poorly developed
-poorly implemented
-inadequate treatment, sample, measurement methods
study purpose
is the researcher trying to
-describe variables
-examine relationships
-determine differences
-test a treatment
non-experimental quanitiative designs
-descriptive studies
-correlational studies
-comparative studies
experimental quanitative designs
experimental or quasi-experimental
descriptive studies
-collect detailed description of exisiting variables
-assess current conditions
-use data to identify problems, improve health care practices, develop theory, guide future research
typical descriptive design
clairifcation->measurement->description->interpretation->developement of hypothesis
correlational studies
explore relationships between or among variable
provide deeper insight into a phenomenon
comparative studies
describes and compares variables in two or more groups
3 essential elements of experimental studies
-randomization
-manipulation of independent variable
-control
treatment protocols for experimental studies
-specify what the intervention will entail
-who will recieve it
-who will administer it, do they need training
-when and for how long
-what will the alternative/control be
common designs of experimental studies
-pretest - posttest
-true experiment, classic experiment
-randomized control trial(RCT)
-posttest only
-crossover
advantages of experimental studies
-more controls; design & conduct of study
-increased internal validity; fewer threats
-fewer rival hypotheses
-more practical to implement
-more feasible: resources, subjects, time, setting
-sometimes more generalizable(comparable to practice)
quasi-experimental studies
researcher initiates experimental tratement but some characteristic of a true experiment is lacking (usually randomization)
common design in quasi-experimental designs
-nonequivalent control group pretest-posttest
-nonequivalent control group post-test only
-one group pretest-posttest
other quantitative studies
-outcomes reserach
-methodological reserach
-meta-analysis
-secondary analysis
-cohort studies
-case control studies
