Informal Experimental Design: An Overview
Informal experimental designs are a less sophisticated approach compared to formal experimental designs and rely on differences in magnitudes for analysis. These designs often involve measuring the dependent variable before and after the introduction of a treatment. In this article, we will explore the different types of informal experimental designs and their characteristics.
Types of Informal Experimental Designs
There are several types of informal experimental designs commonly used in research studies. These designs provide valuable insights into the effects of treatments and interventions. Let’s examine each design in detail.
Before and After without Control Design
In the before and after without control design, a single test group or area is selected for the study. The dependent variable is measured before the treatment is introduced. Subsequently, the treatment is implemented, and the dependent variable is measured again after the treatment. The effect of the treatment is determined by calculating the difference between the levels of the phenomenon before and after the treatment.
This design is simple to implement but may be susceptible to extraneous variations over time, which can influence the treatment effect.
After-Only with Control Design
The after-only with control design involves selecting two groups or areas for comparison. The treatment is introduced in the test area only, while the control area remains untreated. The dependent variable is measured simultaneously in both areas to assess the impact of the treatment. The treatment effect is determined by subtracting the value of the dependent variable in the control area from its value in the test area.
This design assumes that the two areas are identical in terms of their behavior towards the phenomenon under study. Any differences observed between the test and control areas can be attributed to the treatment.
Before and After with Control Design
The before and after with control design is considered the most robust among informal experimental designs. In this design, two areas are selected for the study. The dependent variable is measured in both areas for an identical time-period before the treatment. Then, the treatment is introduced in the test area only, and the dependent variable is measured in both areas for an identical time-period after the treatment. The treatment effect is determined by comparing the change in the dependent variable in the control area to the change in the test area.
This design overcomes the limitations of the other two designs by accounting for extraneous variations over time and non-comparability of the control and test areas. It provides a more reliable estimation of the treatment effect.
Conclusion
Informal experimental designs offer a practical and straightforward approach to studying the effects of treatments and interventions. While they may be less sophisticated than formal designs, they provide valuable insights into the relationship between treatments and dependent variables. Researchers can choose the appropriate design based on the research question and available resources.
Sources:
- “Unit 4: Experimental Design” by Unknown Author (http://ndl.ethernet.edu.et/bitstream/123456789/79399/2/Unit%204%20-%20Experimental%20Design.pdf)
- “Informal Experimental Designs – Experiments” by Unknown Author (https://arts.brainkart.com/article/informal-experimental-designs—experiments-584/)
- “Informal Introduction to Factorial Experimental Designs – Intervention Optimization Initiative” by Unknown Author (https://cadio.org/informal-introduction-to-factorial-experimental-designs/)
FAQs
Informal Experimental Design: An Overview
What is informal experimental design?
Informal experimental design is a less sophisticated approach to experimental design compared to formal designs. It relies on measuring the dependent variable before and after the introduction of a treatment to analyze the treatment’s effect.
What are the main characteristics of informal experimental designs?
Informal experimental designs focus on differences in magnitudes for analysis. They often involve a single test group or area, measuring the dependent variable before and after the treatment, and assessing the treatment effect based on the change in the dependent variable.
What are the different types of informal experimental designs?
There are three common types of informal experimental designs:
– Before and After without Control Design: Measures the dependent variable before and after the treatment in a single test group or area.
– After-Only with Control Design: Compares the dependent variable in two groups or areas, one with the treatment (test area) and one without (control area), at the same time.
– Before and After with Control Design: Measures the dependent variable in two areas for an identical time-period before and after the treatment, comparing the change in the dependent variable.
How does the before and after without control design work?
In this design, a single test group or area is selected. The dependent variable is measured before the treatment is introduced. The treatment is then implemented, and the dependent variable is measured again after the treatment. The treatment effect is determined by calculating the difference between the levels of the phenomenon before and after the treatment.
What is the after-only with control design?
The after-only with control design involves selecting two groups or areas for comparison. The treatment is introduced in the test area only, while the control area remains untreated. The dependent variable is measured simultaneously in both areas to assess the impact of the treatment. The treatment effect is determined by subtracting the value of the dependent variable in the control area from its value in the test area.
How does the before and after with control design differ from other designs?
The before and after with control design is considered the most robust among informal experimental designs. It selects two areas and measures the dependent variable in both areas for an identical time-period before the treatment. The treatment is then introduced in the test area only, and the dependent variable is measured in both areas for an identical time-period after the treatment. The treatment effect is determined by comparing the change in the dependent variable in the control area to the change in the test area.
What are the advantages of informal experimental designs?
Informal experimental designs are relatively easy to implement and provide valuable insights into treatment effects. They can be useful when formal experimental designs are not feasible or when there is a need for quick, preliminary analysis.
What are the limitations of informal experimental designs?
Informal experimental designs may be susceptible to extraneous variations over time and lack control over confounding factors. They may also have limited generalizability and may not provide strong causal evidence compared to formal experimental designs.