True Experimental Design and Single-subject Designs
Synopsis
True-experimental and single-subject design are statistically approach of experimental research that mainly determine if an intervention influences an outcome (Creswell, 2009). True-experimental design establishing cause and effect relationship between different variables. It contains key features which are the independent-dependent variable, Pretesting-Posttesting, and experimental-controlled group where random assignment used to determine in which groups participants will be. Random Assignment is important in experimental research because it ensure that each group are comparable and any differences between groups are due to random chance. According to Skidmore (2008), true-experimental design has three characteristics namely Pretest-Posttest Control Group Design, Posttest-Only Control Group Design (controls possible confounding effect of pretest), and Solomon Four Group Design (corrects possible confounding effects of pretest). Remember that independent variable manipulated in the study where it can cause and affect the outcomes. Another approach of experimental research is applied behavioral analysis or single-subject design (as cited in Creswell, 20009). It is use to implement experimental treatment over time to a single individual or small number of individuals. The researchers differentiate baseline period and intervention period using line graph. According to Siegle (2015), this research has three designs namely A-B design (baseline period and intervention period), A-B-A & B-A-B/ reversal design (discontinuing the intervention and returning to a nontreatment condition or vice versa), and Multiple-Baseline Design (addressing several issues). This design is popular in the field of special education and counselling. Single-subject design is used when the researchers wanted to document the behavior before and after implementing the treatment or intervention.
