It's important to know whether the research you find is of good quality! To determine whether it is, ask yourself a few questions about the resource such as:
Who wrote it? (Were they experts?)
When was it published? (Newer research is usually better)
Where was it published? (Peer-reviewed journal? Government or university site?)
Clear and logical? (Avoid research that sounds extreme or biased)
Backed by evidence? (Look for studies with data, not opinions)
More than one source says the same thing? (Reliable research is supported by multiple studies)
These questions are basic and are great at getting you started at evaluating the research. Further exploration into determining whether research is good quality or not is called critical appraisal and can get very involved! Developing this skill can take some time to develop, but it is an important skill that will serve you throughout your career.
Critical appraisal is an essential skill for nutrition professionals that allows you to systematically evaluate research evidence before applying it to practice. As nutrition science continuously evolves, the ability to distinguish between high-quality and questionable research ensures that your recommendations are based on sound evidence rather than potentially biased or flawed studies. Critical appraisal helps you determine whether research findings are valid, important, and applicable to your specific nutrition practice situations.
Is the article you are reading a randomized control trial (RCT)? Is it a systematic review? Where does it fall on the hierarchy of evidence? Understanding the type of study design used in the article can tell you that study's strengths and weaknesses, as well as what approach to use when appraising it.
Does the article have a clearly stated goal? Who was selected to participate in the study? Were there controls to minimize bias? Was the study completed? This is where the bulk of the appraisal happens and where you need to carefully investigate to make sure the study was appropriately conducted.
What were the big findings? Were results statistically significant and were appropriate statistical tests used? This may require a knowledge of basic statistical findings that can occur in medical literature, but the importance of these values can't be understated. Reach out to your librarian if you have questions or need help with these!
Were the participants in the study similar to the patient you are treating? Is the intervention practical and cost-effective in your setting? Do potential benefits outweigh the harms? Studies give us new and hugely beneficial information, but there needs to be consideration given to whether this new information is applicable and helpful for your patients.
Take stock of the strengths and weaknesses of the article and make a determination is the article's findings might influence your practice. You may also consider that more research is needed before you apply findings.
Systematic Review: A summary of evidence, typically conducted by an expert or expert panel on a particular topic, that uses a rigorous process (to minimize bias) for identifying, appraising, and synthesizing studies to answer a specific clinical question and draw conclusions about the data gathered. (Level I)
Meta-analysis: A process of using quantitative methods to summarize the results from the multiple studies, obtained and critically reviewed using a rigorous process (to minimize bias) for identifying, appraising, and synthesizing studies to answer a specific question and draw conclusions about the data gathered. The purpose of this process is to gain a summary statistic (i.e., a measure of a single effect) that represents the effect of the intervention across multiple studies. (Level I)
Clinical Practice Guidelines: Systematically developed statements to assist clinicians and patients in making decisions about care; ideally, the guidelines consist of a systematic review of the literature, in conjunction with consensus of a group of expert decision makers, including administrators, policy makers, clinicians, and consumers who consider the evidence and make recommendations. (Level I)
Randomized Controlled Trials (RCTs): A true experiment (i.e. one that delivers an intervention or treatment in which subjects are randomly assigned to control and experimental groups); the strongest design to support cause-and-effect relationships. (Level II)
Quasi-experiments: A type of experimental design that tests the effects of an intervention or treatment but lacks one or more characteristics of a true experiment (e.g., random assignment; a control or comparison group). (Level III)
Cohort Studies: A longitudinal study that begins with the gathering of two groups of patients (the cohorts), one that received the exposure (e.g., to a disease) and one that does not, and then following these groups over time (prospective) to measure the development of different outcomes (diseases). (Level IV)
Case-control Studies: A type of research that retrospectively compares characteristics of an individual who has a certain condition (e.g. hypertension) with one who does not (i.e., a matched control or similar person without hypertension); often conducted for the purpose of identifying variables that might predict the condition (e.g., stressful lifestyle, sodium intake). (Level IV)
Cross-sectional Studies: A study designed to observe an outcome or variable at a single point in time, usually for the purpose of inferring trends over time. (These do not have a designated level as these are "a moment in time" and used in many different study designs).
Meta-synthesis: A rigorous process of analyzing findings across qualitative studies. The results address a specific research question and are obtained through the synthesis of qualitative studies. The process allows researchers to find greater meaning through interpreting the qualitative data. (Level V)
Descriptive Studies: Those studies that are conducted for the purpose of describing the characteristics of certain phenomena or selected variables. (Level VI)
Qualitative Studies: Research that involves the collection of data in non-numeric form, such as personal interviews, usually with the intention of describing a phenomenon. (Level VI)
Case Study/Case Reports/Case Series: An intensive investigation of a case involving a person or small group of persons, an issue, or an event. Reports describe the history of a single patient, or a small group of patients, usually in the form of a story.
Experiential and non-research evidence: Literature review, quality improvement, program or financial evaluation.
Background Information/Expert Opinion/Evidence Summaries: Fully referenced expert topic reviews written by recognized authorities who review the topic, synthesize the evidence, summarize key findings, and provide specific recommendations.