1. Efficacy
– Definition: Efficacy refers to the ability of a specific intervention or treatment to produce a desired result under ideal or controlled conditions. It is often assessed in clinical trials or laboratory settings, where researchers can carefully control and monitor variables to measure the intervention’s impact.
– Measurement: Efficacy is typically measured through randomized controlled trials (RCTs) or experimental studies. These studies aim to isolate the effect of the intervention by controlling for confounding variables and ensuring a high level of internal validity.
Calculation Formula: The efficacy of an agent being tested, such as a vaccine, can be expressed in terms of the rates of developing the disease in the vaccine and placebo groups. The formula for calculating efficacy is: [(Rate in those who received the placebo) – (Rate in those who received the vaccine)] / (Rate in those who received the placebo)
2. Effectiveness
– Definition: Effectiveness refers to the ability of an intervention to produce a desired effect in real-world or practical settings, considering a broader and more diverse population than in controlled conditions. It assesses how well a treatment works when applied in everyday, routine circumstances.
– Measurement: Effectiveness is often studied through observational studies or implementation research. These study designs aim to capture the intervention’s impact in more realistic conditions, considering factors like patient adherence, healthcare provider variability, and external influences.
3. Efficiency
– Definition: Efficiency relates to the extent to which resources, such as discomfort, pain, absenteeism, disability, and social stigma, are used to achieve the desired outcome. It involves maximizing the benefit while minimizing waste or unnecessary costs.
– Measurement: Efficiency can be measured through cost-effectiveness analyses, where the costs associated with an intervention are weighed against its outcomes. This involves evaluating the economic value of the intervention and determining whether it provides good value for the resources invested.