Class 9 October 24 Experimental and Quasi-Experimental Research

This design has one manipulated independent variable

This design has two or more independent variables

This design does not have random assignment of subjects to groups or other strategies to control extraneous variables

This design uses randomization and provides maximum control of extraneous variables, has the greatest internal validity

This design lacks randomization but employs other strategies to provide some control over extraneous variables

This is manipulated by the experimenter, also called the treatment, or X

The group that is given the independent variable treatment(s)

The group that does not receive the experimental treatment. Receives a different treatment or none at all.

This design involves three steps: 1). Pretest measuring dependent variable. 2). Applying experiemental treatment to subjects. 3). Administering a posttest, measuring dependent variable.

This design uses two or more preexisting or intact (static) groups, only one of which is exposed to the experimental treatment

This is a scientific investigation, in which the researcher manipulates one or more variables and systematically introduces changes, and observes.

What are the three characteristics of an experiment?

If two situations are equal in every respect except for a variable that is added to or deleted from one of the situations, any difference appearing between t he two situations can be attributed to that variable

If two situations are not equal, but it can be demonstrated that none of the variables except the ind. variable is significant, then any difference occurring between the two situations after introducing a new variable to one of the systems can be attributed to the new variable

The extent to which the changes observed in a dependent variable are, in fact, caused by the independent variable in a particular experimental situations rather than by some extraneous factors. Basic requirement to draw correct conclusions from an experiment

What are the 11 threats to internal validity?
(MDS HIRED PMS)

Specific events or conditions, other than the experimental treatment, may occur in the environment between the first and second measurements and may produce changes in the dependent variable (events occurring at same time as experiment)

Refers to changes (biological or psychological) that may occur within the subjects simply as a function of the passage of time

Exposure to _______ administered before the experimental treatment may affect the subject's performance on a second test, regardless of the treatment

The _____ threat to internal validity is a result of the unreliability of the measuring instruments or a change in the instruments used during the study

Refers to the well-known tendency for subjects who score extremely high or extremely low on a pretest to score closer to the mean (regression toward the mean) on a posttest, regardless of the treatment

Is a threat when there are important differences between the experimental and control groups even before the application of the experimental treatment, occurs when intact groups must be used (not randomized)

This threat occurs when there is differential loss of participants from the comparison groups

This threat involves unintentional effects that the researcher himself has on the study, example is gender, race, position

Subjects attitudes developed in response to the research situation that can be a threat to internal validity

Type of subject effect in which the subject knows they are in a research study

Type of subject effect in which the control group exerts extra effort

Type of subject effect in which subjects feel they are receiving less desirable treatment or being neglected

Occurs when participants in one group (typically the experimental group) communicate information about the treatment to subjects in the control group in such a way as to influence the latter's behavior on the dependent variable

What are 6 ways to deal with threats to internal validity?

Explain this:
0-X-0
_________
0-*-0

0=
X=
_____=
*=
(R)=
(M) -

Explain this:
0-X-0

What are the internal validity threats to the One-Group Pretest Posttest?

What are the internal validity threats to Static Group Comparison?

Explain this:
(R) - X - 0
___________
(R) - *-0

What are the internal validity threats to PostTest Only Control Group?

Explain this:
(M)-X-0
__________
(M) - * - 0

What are the internal validity threats to Matched Posttest Only Control Group?

Explain This:
(R)0-X-0
__________
(R)0-*-0

What are the internal validity threats to Pretest Posttest Only Control Group?

Explain this:
(R)0-x-0
__________
(R)0-*-0
__________
(R)*-X-0

What are the internal validity threats to Solomon Three Groups?

Explain this:
(R)0-X-0
__________
(R)0-*-0
_________
(R)*-X-0
__________
(R)*-*-0

What are the internal validity threats to Solomon Four Groups?

Explain this Quasi-Exp Design:
0-X-0
______
0-*-0

What are the internal validity threats to Nonrandom Control Group Pretest Posttest?

Explain this:
B-C-D
A-D-B
D-A-C
C-B-A

What are the internal validity threats to Counterbalance Design?

Explain this:
01-02-03-04-X-05-06-07-08

What are the internal validity threats to One Group Time Series Designs?

Explain this:
01-02-03-04-X-05-06-07-08
___________________________
01-02-03-04-*-05-06-07-08

What are the internal validity threats to the Control Group Time Series Design?

This is the extent that the results of an experiment can be generalized to different groups, settings, and measuring instruments.

What are the three types of external validity?

This external validity is related to the way subjects are selected for a study

What is a threat to population external validity?

This external validity is able to generalize the results of the research to other situations, considers the environment in which the research was done.

What are the threats to Ecological External Validity?

This external validity asks if similar results would be expected from different investigators with different operational definitions/procedures.

What are the 6 threats to external validity?

How can you deal with threats to external validity?

A study is ______ to the extent that the effect of influences, beyond the experimental variable, has been removed or minimized

A study is _______ to the extent that the subjects, experimental arrangements, and procedures are representative of the target setting, thus making results generalizable.

______ is a pre-requisite for external validity