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• Chapter 3 addresses how a researcher answers the questions specified in Chapter 1.

Methods of Study and Sources of Data

• These include research design, respondents of the study, data-gathering instrument, data-gathering procedure, and statistical treatment.

Research Design

• The mode of research used is vital in research execution.

Types of Research Design

• Descriptive design involves observational studies that describe "what is," where variables are uncontrolled, and no intervention is applied.
• An example of descriptive design is a description of teenagers' attitudes towards smoking.
• Correlational design explores and observes relationships among variables.
• In correlational desgin variables are not controlled and no intervention is applied
• An example of correlational design is a study of the relationship between IQ and clinical depression.
• Quasi-experimental design tests for causality with suboptimal variable control where the independent variable is not manipulated and an intervention is applied.
• An example of quasi-experimental design is a study of the effect of an after-school physical activity program on childhood obesity rates.
• Experimental design tests causality with optimal variable control, where the independent variable is manipulated, and an intervention is applied.
• An example of experimental design is a study of the effects of a new diet treatment plan on insulin levels in diabetics.

Non-Experimental Designs

• Survey studies and considerations for time orientation are components of non-experimental designs.
• Time orientation includes retrospective, cross-sectional, and longitudinal studies.
• Purpose/objective considerations include descriptive, comparative, correlational, and evaluative studies.

Survey Studies

• Investigations are conducted through self-report.
• Respondents report on their attitudes, perceptions, or behaviors.
• These studies aim to describe characteristics, opinions, and attributes as they currently exist in a population.

Time Orientation: Retrospective Study

• The outcome of interest has already occurred when the study is initiated.
• Allows investigators to formulate ideas about possible associations and investigate potential relationships.

Time Orientation: Cross-Sectional Study

• Data is collected at a single point in time requiring subjects at different points or phases of an experience.
• Subjects are assumed to represent data collected from different time periods.

Time Orientation: Longitudinal

• Data is collected from the same people at different times.

Purpose or Objective: Descriptive

• Aims to gather more information on certain characteristics within a particular field of study.

Purpose or Objective: Comparative

• Used to compare and contrast representative samples from two or more groups of subjects in relation to the variables involved.

Purpose or Objective: Correlational

• Used to investigate the direction and magnitude of relationships among variables in a particular population.

Purpose or Objective: Evaluative

• Involves making a judgment of worth or value.
• Allows the researcher to provide information that is useful for judging when conducting a program or service.
• It can be formative (ongoing) or summative (end of program) in nature.

Experimental Designs

• True experiment designs, quasi-experimental designs, and pre-experimental designs all fall under the umbrella of experimental designs.

True Experimental Design

• A design is considered a true experiment when the researcher manipulates the independent variable.
• The research has control, and there is at least one experimental and one comparison/control group.
• The subjects are randomly assigned.
• The control group does not receive the treatment.

Pretest-Posttest Control Group Design

• R represents random selection, O1 is the pretest, X is the intervention, and O2 is the posttest.
• Experimental group design is RO1 X O2
• Control group design is RO1 O2

Posttest Only Control Group Design

• R is random selection, X is the intervention, and O2 is the posttest.
• Experimental design is RX O2
• Control group design is RO2

Solomon Four-Group Design

• R is random selection, O1 is the pretest, X is the intervention, and O2 is the posttest
• The design is RO1 X O2, RO1 O2, RX O2, and R O2.

Quasi-Experimental Design

• A design in which either there is no control group or the subjects are not randomly assigned to groups.

Non-Equivalent Control Group Design

• O1 is pretest, X is the intervention, and O2 is the post test.
• Experimental design is O1 X O2
• Control group design is O1 O2

Time-Series Design

• O1, O2, and O3 are pretests, X is the intervention, and O4, O5, and O6 are posttests.
• The design is O1 O2 O3 X O4 O5 O6

Pre-Experimental Design

• A design in which the researcher has little control over the research and is therefore a very weak design.

One-Shot Case Study

• X refers to intervention
• O refers to observation after intervention
• The design is XO

One-Group Pretest Post-Test Design

• O1 is the pretest, X is the intervention, and O2 is the posttest.
• The design is O1 X O2