Objectives

Topics 1
Research Design

Topic 2
Designs for Nursing Research

Topic 3
Concepts Relevant to Design

Topic 4
Design Validity

Topic 5
Good Study Design

Topic 6
Modeling study design

References

TOPIC 6:
Modeling study design

Quasi-experimental and experimental study designs can be mapped to facilitate understanding the design. The symbol O is used to identify an observation point, or the point in time in which measurement of the DVs is done. A number subscript indicates which observation/ measurement is being done. The symbol T or X is used to identify administration of intervention/ treatment, which will occur only in the experimental group.

• A simple pretest-posttest design with an experimental and a control group would look like this:
  

  Experimental group	O1	T	O2
  Control group	O1		O2
  The diagram would look the same for a quasi-experimental study but the control group would be called the comparison group.

• A posttest only design
  

  Experimental group	T	O
  Control group		O

• If the intervention/ treatment is administered three times with measures taken after each intervention/ treatment it would look like this:
  

  Experimental group	O1	T	O2	T	O3	T	O4
  Control group	O1		O2		O3		O4