single case experiment
an experiment in which the effect of the independent variable is assessed using data from a single participant
in a single case design, the subject's behaviour during a control period before introduction of the experimental manipulation
a single case design in which the treatment is introduced after a baseline period and then withdrawn during a second baseline period. It may be extended by adding a second introduction of the treatment. Sometimes called a "withdrawal" design.
multiple baseline design
observing behaviour before and after a manipulation under multiple circumstances (across different individuals, different behaviours, or different settings).
research designed to evaluated programs (e.g., social reforms, innovations) that are designed to produce certain changes or outcomes in a target population
studies that ask whether there are, in fact, problems that need to be addressed in a target population
program theory assessment
may involve the collaboration of researchers, service providers, and prospective clients of program to determine that the proposed program does in fact address the needs of the target population.
Program evaluation in which researcher monitors program to determine whether it is reaching target population, attracting enough clients, and staff is providing planned services.
(are intended outcomes of program being realized?) Researcher devises way of measuring outcome and studies impact of program on outcome measure.
final program. After program has shown it has its intended effect, determine if it is 'worth it.' cost of program vs benefits.
a type of design that approximates the control features of true experiments to infer that a given treatment did have its intended effect
one-group posttest-only design
a quasi-experimental design that has no control group and no pretest comparison; a very poor design in terms of internal validity
one-group pretest-posttest design
a quasi-experimental design in which the effect of an independent variable is inferred from the pretest-posttest difference in a single group
as a threat to the internal validity of an experiment, refers to any outside event that is not part of the manipulation that could be responsible for the results
as a threat to internal validity, the possibility that any naturally occurring change within the individual is responsible for the results
a threat to internal validity in which taking a pretest changes behaviour without any effect on the independent variable.
as a threat to internal validity; the possibility that a change in the characteristics of the measurement instrument is responsible for the results.
statistical regression (regression toward the mean)
principle that extreme scores on a variable tend to be closer to the mean when a second measurement is made.
nonequivalent control group design
a quasi-experimental design in which nonequivalent groups of subjects participate in the different experimental groups, and there is no pretest
differences in the type of subjects who make up each group in an experiment design; this situation occurs when participants elect which group they are to be assigned to.
nonequivalent control group pretest - posttest design
a quasi-experimental design in which nonequivalent groups are used, but a pretest allows assessment of equivalency and pretest-posttest changes.
interrupted time series design
a design in which the effectiveness of a treatment is determined by examining a series of measurements made over an extended time period both before and after the treatment is introduced. The treatment is not introduced at a random point in time.
control series design
an extension of the interrupted time series quasi-experimental design in which there is a comparison or control group.
a developmental research method in which persons of different ages are studied at only one point in time; conceptually similar to an independent groups design.
a developmental research method in which the same persons are observed repeatedly as they grow older; conceptually similar to a repeated measures design.
a group of people born at about the same time and exposed to the same societal events; cohort effects are confounded with age in a cross-sectional study