Intervention or Observational - What's the Difference?

Intervention vs. Observational

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Anyone working in the clinical trials sphere will be familiar with two important terms when conducting research: Intervention and Observational. Both study types are important but are fundamentally different - here's why and what it could mean for your research.

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Interventional studies set out to try or test an intervention which might be a nutriceutical, supplement, drug, medical device, procedure, activity or something else. They may or may not be new or novel. Here are some examples of interventions which are typically used in research:

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• Nutriceutical: Probiotics, nutritional extracts and foods
• Supplement: Vitamins or minerals typically used in foods
• Drug: Antiviral or anticancer therapies
• Medical Device: Portable wearables for blood glucose measurement
• Procedure: Changes in post-operative care protocols
• Activity: High-Intensity Interval Training (HIIT)

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The role of the placebo and of blinding are important in such studies, however, not every situation can adapt to this format. For example, if there is a known effective therapy in-place already, the control group would likely be fully aware that they were receiving this intervention as a historic and industry-accepted protocol (e.g. the administration of statins for cholesterol-lowering, or stent placement in atherosclerosis).

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Intervention studies are essential for comparing two methods, practices or treatments to establish any benefit of one over the another.

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Observational studies are typically much less invasive and resource demanding. No new interventions are tested and the study might involve, as the name suggests, observation over time. If a new approved medication is used, an observational study might, for example, involve monitoring people at specific time points to determine longitudinal effects which were not tested in the initial intervention period of that therapy itself.

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Observational studies are extremely useful for assessing the current state of affairs for health, particularly in more context-specific situations. Are intervention items tested still effective in the wider population? Are they as effective as they were, say, 35 years ago? Were there unforeseen issues which are now becoming visible in a niche group as more data are becoming available?

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It's also important to note that since treatment regimens or strategies are not altered in an observational study, you might be able to participate in multiple observational studies at the same time.