EXPERIMENTAL DESIGN The investigator planning an experiment has many experimental design option to choose. Experimental designs fall into two major categories. True or Classical experimental design Pre- experimental design

TRUE OR CLASSICAL EXPERIMENTAL DESIGN There are three major subdivisions in true or classical experimental design Pre test post test control group design Solomon four group design After / post test only experimental design

PRE TEST POST TEST CONTROL GROUP DESIGN Experimental group experimental treatment Pre testPost test

Control group Pre testPost test

PRE TEST POST TEST CONTROL GROUP DESIGN In this design, subjects have been designed randomly to the experimental or control group The experimental treatment is given only to those in the experimental group, and the pre tests and post tests are those measurements of the dependent variables that are made before and after the experimental treatment is performed. All true experimental designs have subjects randomly assigned groups, have an experimental treatment introduced to some of the subjects and have the effects of the treatment observed. Advantages The investigator is able to account for events occurring between time 1 and time 2 through observation of control group It also enables the investigator to control for changes in the instrumentation, since changes or drifts in measurement should affect both groups equally Randomization decreases selection bias and maturation.

SOLOMON FOUR GROUP DESIGN Experimental group I experimental treatmentPre test Post test

Control group I

Pre test Post test

Experimental group II experimental treatment Post test

Control group II Post testSOLOMON FOUR GROUP DESIGN This design employs two experimental groups and two control groups. Initially, the investigator randomly assigns subjects to the four groups. Those in the first experimental treatment, and observed again on occasion 2. Those in the experimental group 2 also receive the treatment but are observed only after the treatment, nor before. Those in control group 1 are observed, on occasion 1 and 2, but they are not given the experimental treatment. Those in control group 2 are observed only on the second occasion without previous observation or treatment.ADVANTAGES It has great potential for generating information about differential sources of effect on the dependent variable, because all four groups are studied at the same time, both the effects of events occurring between time 1 and time 2 and the maturation of subjects are controlled. One can examine the score of control groups 2 for a measure of maturation without the influence of treatment. The invigilator also can compare the different in the groups.

AFTER / POST TEST ONLY CONTROL GROUP DESIGN Experimental group experimental treatment Post test

Control group Post testADVANTAGE This design can be useful in situation where it is not possible to pretest the subjects or pretest is non essential

PRE-EXPERIMENTAL DESIGN It is one type of the experimental design It have three subdivisions. They are One short case study or single case study One group pretest posttest design The static group comparison design

ONE SHORT CASE STUDY OR SINGLE CASE STUDY Experimental treatment Cause change In single case study, that studies at once, following a treatment or an agent presumed to cause change.

Because the study design has a total absence of control, it is considered to be little value as an experiment.

ONE GROUP PRETEST POSTTEST DESIGN

Experimental treatment

Pre test post test

Here only one group is observed before and after the independent variable is introduced.

Loss of the control group decreases the usefulness of the study but may be necessary in cases where it is not possible or feasible to have control groups.

THE STATIC GROUP COMPARISON DESIGN The static group that has experienced the independent variable is compared with one that has not.

Here the experimental group received the independent variable, but control group did not receive the independent variable.MICHELLE ANDREA A. DEMAGUIL, RN