Chapter 13: Quasi-experiments and small-N design Flashcards
quasi-experiment
a study, similar to an experiment except that researchers don’t have full experimental control
quasi-independent variable
a variable that resembles an independent variable but researchers don’t have full control over it
nonequivalent control group posttest-only design
participants are not randomly assigned to groups and are only tested once after exposure to one level of the independent variable or the other
nonequivalent control group pretest/posttest design
participants are not randomly assigned to groups and are tested before and after some intervention
interrupted time series design
a quasi-experiment in which participants are measured repeatedly on a dependent variable before, during, and after the “interruption” caused by some event
nonequivalent control group interrupted time series design
a quasi-experiment with 2 or more groups in which participants haven’t been randomly assigned to a group and they are also measured before, during, and after an interruption caused by some event
- the presence or timing of the interrupting even differs among the 2 groups
wait-list design
an experimental design for studying therapeutic treatment in which researchers randomly assign some participants to recieve the therapy immediately and others to recieve it after a time delay
large-n designs
- participants are grouped: data from all participants in each group are combined and studied together
- data are represented as group averages
- large samples enable group averages to be estimated more precisely
- used for both basic and applied research
small-n designs
-each participant is treated seperately: small-n designs are almost always repeated measured designs, in which researchers observe how participants respond to several systematically designed conditions
- data for each individual are presented
- careful designs enable researchers to compare each individual during treatment and control periods
- used in therapeutic settings, to confirm that a treatment works for an individual person
stable-baseline design
a small-n design in which a researcher observes behavior for an extended baseline period before beginning a treatment or other intervention, and continues observing behavior after the intervention
multiple-baseline design
a small-n design in which researchers stagger their introduction of an intervention across a variety of contexts, times, and situations
reversal design
researchers observe a problem behavior both before and during treatment and then discontinue the treatment for a while to see if the problem behavior returns
single-n design
a study in which researchers gather information from only one person or animal
