When sourcing medical evidence to support your writing, it can sometimes be difficult to find reliable studies, as not all research is conducted in the same way. We’ve discussed the importance of finding evidence from top medical journals, but how do you know which studies are worth including in your writing?
High-quality studies are those that are objective, have a rigid study design with outcomes, and use multiple analyses for statistical significance. To be able to thoroughly assess the quality of a study – and although reading the abstract is useful when selecting a study from a large search – accessing the full journal article allows you to properly assess the elements of study.
By critically appraising articles to include only high-quality studies for your writing projects, you can enhance your reputation as a writer by ensuring your content is relevant, accurate and reliable.
Here are five ways to help you assess whether a study is high quality.
1. Sample size
You can assess whether a study’s results may be clinically relevant by noting the sample size of selected participants enrolled in the study, also known as the study power.
A good sample size allows enough patients to distinguish between treatments and can ensure the results are statistically significant and not due to a random occurrence (statistically this will show in the results with 95% confidence interval and p < 0.05).
Generally, studies with higher numbers of participants give a broader range of results and better confidence for statistical results that are representative of the true population.
2. Study design
Although there are many different types of clinical trial design, two broad types of studies exist; experimental studies measure the outcome of a treatment, test, procedure or program; and observational studies that provide information about the effects of a risk or treatment.
Randomised-controlled trials (RCT) are usually considered the best study design. However sometimes a RCT that is double-blinded and placebo-controlled may not be a high-quality study. The study design rests on how it well it was executed factoring in rigour, creativity and technical prowess. This includes understanding who were the experts were involved in the design, how the statistical analysis was performed, protocols applied, ethics approval and documentation procedures.
Assessing the study design means when you’re reading the methods, take note of baseline characteristics, duration of follow up, was the study performed over multiple sites and how does it compare to previously performed studies.
The study’s null hypothesis should clearly outline the primary (and where relevant secondary) endpoints that are to be tested. Usually studies have two or three hypothesised endpoints that are discussed later on based on the results. However apply caution with studies that test multiple endpoints, as the results may be too broad to be clinically relevant.
When setting out the hypothesis, a high-quality study should also explain how the hypothesis fits in with past research and how it advances current knowledge.
4. Inclusion and exclusion criteria
A study’s inclusion criteria can influence study bias and ultimately the conclusions for the study’s hypothesed endpoints.
You may check how the study participants were selected or whether targeted groups of patients have been systematically excluded from the study, such as very sick patients who could skew the results.
Every study should have an explanation for how patients were selected and you should apply caution if you read a study that does not define their inclusion or exclusion criteria. Study bias is a key influencer of results and can change the way results are interpreted.
5. Relevance and appropriateness
The appropriateness of a study is fundamental when applying evidence to the ‘real world’ in your writing. You may need to consider how similar the population tested in the study compares to population the intervention would be applied.
Keep a checklist (mental or physical) to help you assess the relevance of the study, and consider a few questions; are the findings from local or international patient populations? Does the study participants have comorbidities or other differences to patients in the population you are writing about? Are the patients representative of the general population?
Assessing baseline characteristics of the patients recruited for the study can help you understand the overall scope of the findings and its application for patients in clinical practise.
Do you have a checklist for evaluating studies when you read them? Feel free to share what you look for in the comments below.