Which level of evidence study design is based on a single group with a non-randomized approach?

Which level of evidence study design is based on a single group with a non-randomized approach?

• A. Case-controlled studies
• B. Descriptive studies
• C. Before/after studies
• D. Expert opinions

Answer: (C)

The answer is before/after studies, as this study design typically involves a single group being measured before and after an intervention without the use of randomization. These studies are useful for assessing changes that occur due to a specific intervention, making them valuable in various fields, including pediatric occupational therapy. In before/after studies, researchers can observe the effects of treatment or interventions on the same group of subjects over time, allowing them to track progress and effectiveness. This approach helps to establish a cause-and-effect relationship between the intervention and the observed outcomes, albeit with limitations inherent to non-randomized designs, such as potential confounding variables. In contrast, other study designs mentioned have different characteristics. Case-controlled studies compare groups for specific outcomes but focus on identifying correlations rather than measuring changes over time within the same group. Descriptive studies primarily provide an overview or snapshot of a population or phenomenon without establishing causal relationships. Expert opinions, while valuable, do not represent empirical evidence derived from structured research methodologies. Each of these alternatives serves a purpose but does not align with the specific features of the before/after study design, which is grounded in a single, non-randomized group approach.

The answer is before/after studies, as this study design typically involves a single group being measured before and after an intervention without the use of randomization. These studies are useful for assessing changes that occur due to a specific intervention, making them valuable in various fields, including pediatric occupational therapy.

In before/after studies, researchers can observe the effects of treatment or interventions on the same group of subjects over time, allowing them to track progress and effectiveness. This approach helps to establish a cause-and-effect relationship between the intervention and the observed outcomes, albeit with limitations inherent to non-randomized designs, such as potential confounding variables.

In contrast, other study designs mentioned have different characteristics. Case-controlled studies compare groups for specific outcomes but focus on identifying correlations rather than measuring changes over time within the same group. Descriptive studies primarily provide an overview or snapshot of a population or phenomenon without establishing causal relationships. Expert opinions, while valuable, do not represent empirical evidence derived from structured research methodologies. Each of these alternatives serves a purpose but does not align with the specific features of the before/after study design, which is grounded in a single, non-randomized group approach.