Chapter 9: Experimental and Quasi-Experimental Designs

Question 1

a priori

Answer 1

From Latin: the former; before the study or analysis

Question 2

after-only design

Answer 2

An experimental design with two randomly assigned groups – a treatment group and a control group. This design differs from the true experiment in that both groups are measured only after the experimental treatment

Question 3

after-only nonequivalent control group design

Answer 3

a quasi-experimental design similar to the after-only experimental design, but subjects are not randomly assigned to the treatment or control groups

Question 4

antecedent variable

Answer 4

a variable that affects the dependent variable but occurs before the introduction of the independent variable

Question 5

attention control

Answer 5

operationalized as the control group receiving the same amount of “attention” as the experimental group

Question 6

control

Answer 6

measures used to hold uniform or constant the conditions under which an investigation occurs

Question 7

dependent variable

Answer 7

in experimental studies, the presumed effect of the independent or experimental variable on the outcome

Question 8

design

Answer 8

the plan or blueprint for conduct of a study

Question 9

effect size

Answer 9

an estimate of how large of a difference there is between intervention and control groups in summarized studies

Question 10

experimental design

Answer 10

a research design that has the following properties: randomization, control, and manipulation

Question 11

extraneous design (mediating variable)

Answer 11

variable that interferes with the operations of the phenomena being studied

Question 12

independent variable

Answer 12

the antecedent or the variable that has the presumed effect on the dependent variable

Question 13

intervening variable

Answer 13

a variable that occurs during an experimental or quasi-experimental study that affects the dependent variable

Question 14

intervention fidelity

Answer 14

the process of enhancing the study’s internal validity by ensuring that the intervention is delivered systemically to all subjects

Question 15

manipulation

Answer 15

the provision of some experimental treatment, in one or varying degrees, to some of the subjects in the study

Question 16

mortality

Answer 16

the loss of subjects from time 1 data collection to time 2 data collection

Question 17

nonequivalent control group design

Answer 17

a quasi-experimental design that that is similar to the true experiment, but subjects are not randomly assigned to the treatment or control groups

Question 18

one-group (pretest-posttest) design

Answer 18

Design used by researchers when only one group is available for study. Data are collected before and after an experimental treatment on one group of subjects. In this type of design, there is no control group and no randomization

Question 19

power analysis

Answer 19

the mathematical procedure to determine the number for each arm (group) of a study

Question 20

quasi-experimental design

Answer 20

a study design in which random assignment is not used, but the independent variable is manipulated and certain mechanisms of control are used

Question 21

randomization (random assignment)

Answer 21

a sampling selection procedure in which each person or element in a population has an equal chance of being selected to either the experimental group or the control group

Question 22

randomized controlled trial (RCT)

Answer 22

a research study using a true experimental design

Question 23

Solomon four-group design

Answer 23

an experimental design with four randomly assigned groups – the pretest-posttest intervention group, the pretest-posttest control group, a treatment or intervention group with only posttest measurement, and a control group with only posttest measurement

Question 24

testing

Answer 24

the effects of taking a pretest on the scores of a posttest

Question 25

time series design

Answer 25

A quasi-experimental design used to determine trends before and after an experimental treatment. Measurements are taken several times before the introduction of the experimental treatment, the treatment is introduced, and measurements are taken again at specified times afterward

Question 26

treatment effect

Answer 26

the impact of the independent variable/intervention on the dependent variable

Question 27

true (classic) experiment (pretest-posttest control group design)

Answer 27

In this design, subjects are randomly assigned to an experimental or control group, pretest measurements are performed, an intervention or treatment occurs in the experimental group, and posttest measurements are performed