About Systematic Reviews

The Differences Between a Randomized-Controlled Trial vs Systematic Review

Policymakers or system implementers are required to make critical decisions that will impact current and future strategies. For decisions to be effective and unbiased, they must be based on solid, irrefutable, and relevant evidence. Therefore, you have to review as many studies as possible to gather enough data to support crucial decisions. A failure to review all the relevant eligible studies may lead to inconsistent results. This is where different types of reviews, including systematic reviews and integrated reviews (among others), become essential.

Through these reviews, you’ll be able to evaluate available literature and collect credible data that can be used as evidence to base decisions on. But you need to understand the pros and cons of each type of review so that you can choose the one that fits your objectives. Fortunately, you can find numerous online resources that talk about the differences between an integrated review vs systematic review, a rapid review vs systematic review, and many other comparisons. This article compares a systematic review with a randomized-controlled trial (RCT).

Systematic Review

A systematic review uses a clearly defined research question to make an assessment leveraging a systematic and reproducible method to find, choose and analytically assess all pertinent research. It gathers and analyzes eligible studies from reputable research sources to support the evidence. The main point to remember from this systematic review definition is that the review needs to answer a specific research question. The research question, which should be clearly stated, the study objectives, and the topic of study define the scope of the study. The scope of the study prevents the author from going against the intention of the conducting review.

You’ll need to develop and register your systematic review protocol, including the rationale for your review and eligibility criteria. This protocol is important for planning your systematic review to prevent issues or challenges in results to be uncovered in the future. It also allows other reviewers to understand the steps that were taken during a systematic review before they begin going over it. This makes the review reproducible and open to quality assessment.

Randomized-Controlled Trial

An RCT is a type of scientific trial meant to control factors that aren’t under direct experimental control. A perfect example of an RCT is a clinical trial aiming to assess the effects of pharmacological treatment, surgical procedure, medical apparatus, diagnostic procedure, or other medical intervention.

This type of study randomly assigns participants (or subjects) to either experimental groups (EG) or control groups (CG), ensuring there isn’t any bias involved in the assignments. The defining aspect of RCTs is that the allocation of participants to either an EG or CG is completely randomized. The assignment may be blinded or not. Not only the participants but also the assessment professionals may be blinded to the group allocations. Also, during the course of the trial, participants may be single-blinded, double-blinded, or not blinded at all. The experimental group in an RCT receives the dose or procedure, while those in the control group receive a placebo, a different type of treatment, or no treatment at all. The state of an RCT being “double-blind”, means that no one knows who is assigned to which group, so there is no way to influence the results.

There are several advantages and disadvantages of using an RCT format. For instance, because an RCT ensures that possible population biases are not a factor in the results, you are assured of receiving impartial evidence that can help you to make informed decisions.

Unlike observational studies, the subjects and researchers involved in a double-blind RCT study don’t know which subjects are receiving the treatment. Masking is essential in medical trials that rely on subjective outcomes to ensure that the drug being evaluated does what it is intended to do. With an RCT, it’s easier to analyze results because you’re using recognized statistical tools, and the population of participants is clearly defined.

However, an RCT can be costly and time-consuming because it requires a large number of participants for more statistical power, and a longer duration to do all of the follow-up analysis. But you can keep the cost of your RCTs down by conducting simple, single, and easily assessed outcome measures.

Just as an RCT requires you to specify the standards used for deciding which participants should be included in the study, a systematic review requires you to define upfront clear standards for deciding which type of research will be included. While an RCT is considered one of the best study designs available, it may not answer all clinical questions. Hence, sometimes you may have to add observational research to your study design as well.

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