Types of Questions/Studies
This study type can help answer many types of clinical questions and is often the best fit when clinicians want to understand what the overall body of research evidence shows across multiple studies addressing the same focused clinical question.
What is a systematic review?
A systematic review is a form of evidence synthesis that uses a structured, transparent process to identify, select, appraise, and summarize studies addressing a focused clinical question.
This international organization is known for producing high-quality systematic reviews that summarize evidence about the effectiveness of healthcare interventions.
What is the Cochrane Collaboration?
The Cochrane Collaboration is an international organization that produces systematic reviews to help clinicians, researchers, and patients make evidence-informed healthcare decisions. Cochrane reviews are often considered a strong source of synthesized evidence, especially for intervention questions.
This information is essential to determine whether the comparison between groups is fair.
What are baseline characteristics? OR What is baseline similarity or baseline comparability?
Baseline characteristics help clinicians determine whether groups were similar before the intervention began. If one group starts with less pain, better function, fewer comorbidities, or different demographic characteristics, these differences may influence the results and make it harder to interpret the true effect of the intervention.
A study reports a value of 0.03 to show whether the difference between the treatment group and control group was likely due to chance.
What is a p-value?
A p-value helps determine whether a result is statistically significant. In simple terms, it helps us judge whether the study finding is likely due to chance. A p-value less than the predetermined alpha level, commonly 0.05, is often considered statistically significant.
These are the steps of EBP.
What are Ask, Acquire, Appraise, Apply, and Assess?
The five steps of EBP are commonly described as the 5 A’s: ask a focused clinical question, acquire the best available evidence, appraise the evidence, apply it with clinical expertise and patient values, and assess the outcome/process
A clinician wants a concise, evidence-based summary of recommendations for the examination and treatment of patients with low back pain. This type of resource is designed to translate current evidence into practice recommendations.
What are clinical practice guidelines?
Clinical practice guidelines, or CPGs, provide evidence-based recommendations to help guide clinical decision-making. They are useful when clinicians want a summary of current best evidence and recommendations for practice.
A student is looking for evidence on the accuracy of a clinical test used in physical therapy practice. This free database is specifically designed to help users find primary studies and systematic reviews of diagnostic test accuracy.
What is DiTA?
DiTA stands for Diagnostic Test Accuracy database. It is a free database that indexes primary studies and systematic reviews of diagnostic test accuracy related to PT practice.
This helps readers judge whether the authors of a systematic review followed a planned method or made decisions after seeing the results, which could increase risk of bias.
What is a systematic review protocol?
Protocols are important because they document the planned methods before the review is completed. This supports transparency, reduces selective decision-making, and helps readers evaluate whether the final review followed the original plan.
A systematic review includes a quantitative statistical analysis to combine results from studies with populations, interventions, outcomes, and follow-up times that are similar enough to be pooled.
What is a meta-analysis?
A meta-analysis is a statistical method used within some systematic reviews to quantitatively combine the results of multiple studies. It is appropriate when the included studies are similar enough in design, population, intervention or exposure, outcome measures, and follow-up time. Not all systematic reviews include a meta-analysis.
This is the best interpretation when a treatment effect has a p-value less than 0.05, and the amount of improvement is smaller than the MCID.
What is statistically significant but not clinically relevant?
Statistical significance means the result is unlikely to be due to chance based on the selected alpha level. Clinical relevance requires the size of the change to be large enough to matter to patients, often judged using the MCID.
This primary study design is often the best fit when the clinical question asks, “Which patient characteristics measured at baseline are associated with future outcomes such as recovery, recurrence, disability, or return to work?”
What are cohort studies?
Cohort studies are appropriate for prognosis/prognostic factors because they observe a defined group over time and examine whether specific baseline factors are associated with later outcomes.
A student is building a PubMed search for this clinical question: “In adults with chronic low back pain, does exercise therapy improve pain and function compared with usual care?” To begin the search, the student should usually start with these two PICO elements as the main search terms.
What are the population and intervention?
For intervention questions, the population/problem and intervention are often the best key terms to start the search. In this example, the student might begin with terms such as chronic low back pain and exercise therapy. The comparison and outcome can be added later if the search results are too broad, but including too many PICO elements at the beginning may make the search too narrow.
This is the minimum database-search expectation when judging whether the search strategy in a systematic review or clinical practice guideline was comprehensive enough.
What are at least two databases?
Searching at least two databases helps make the search more comprehensive and reduces the chance that important studies were missed.
A study reports that the treatment group improved more than the control group. This value helps us understand how large or meaningful the difference was, not just whether the result was statistically significant.
What is effect size?
Effect size describes the magnitude or size of a difference, association, or treatment effect. While a p-value helps determine whether a result is statistically significant, the effect size helps determine whether a result is clinically relevant/important.
A student wants to find evidence about the measurement properties of an outcome measure, including validity, reliability, and responsiveness. This database is designed to help users locate systematic reviews of health measurement instruments.
What is the COSMIN database?
The COSMIN database helps users find systematic reviews about health measurement instruments and their measurement properties. I
When CPGs, systematic reviews, RCTs, and non-RCTs are not available for a PICO question, this lower-level evidence may still be considered with caution
What is a case series?
Case series may be considered when higher-quality evidence is not available for a specific clinical question. However, because case series do not include a comparison group and have a higher risk of bias, they should be interpreted cautiously.
When searching PubMed, these standardized subject headings can help identify articles even when authors use different words for the same concept, such as “low back pain” and “lumbar pain.”
What are MeSH terms?
MeSH stands for Medical Subject Headings. MeSH terms are standardized vocabulary terms used in PubMed/MEDLINE to organize and index articles by topic. They can help improve a search by capturing articles that use different wording for the same concept. However, very new articles may not have MeSH terms assigned yet, so students may need to combine MeSH terms with keywords.
In a well-conducted systematic review, these steps should be completed by at least two independent reviewers to reduce errors, improve consistency, and limit selection or judgment bias.
What are title/abstract screening, full-text study selection, data extraction, and risk-of-bias or methodological quality assessment?
A diagnostic test has high sensitivity. When the patient’s test result is negative, the clinician can use this mnemonic to remember that the condition is less likely and may be ruled out.
What is SNOUT?
SNOUT stands for Sensitive test, Negative result, rules OUT. In diagnostic accuracy, a highly sensitive test is useful for ruling out a condition when the test result is negative. This does not mean the condition is impossible, but it makes the condition less likely.
A prognostic study reports that patients who met physical activity guidelines had an odds ratio of 0.70 for persistent low back pain compared with patients who did not meet the guidelines.
This is the percent reduction in odds for persistent low back pain.
What is 30% reduced odds?
When an odds ratio is less than 1, the outcome has lower odds in the comparison group than in the reference group. To calculate the percent reduction in odds, use 1 − OR. In this example, 1 − 0.70 = 0.30, so the interpretation is 30% reduced odds of persistent low back pain. This refers to reduced odds, not reduced risk
This primary study design is often the best fit when the clinical question asks, “How accurately does a clinical test identify whether a condition is present or absent compared with a reference standard?”
What are cross-sectional studies?
Cross-sectional studies are commonly used for diagnostic accuracy questions because the patient’s clinical test result and reference standard result are usually measured during the same general time period.
A student is searching PEDro for evidence related to PT interventions. This database includes these three major types of evidence.
What are clinical practice guidelines, systematic reviews, and randomized controlled trials?
PEDro is a PT evidence database that indexes randomized controlled trials, systematic reviews, and clinical practice guidelines related to physiotherapy interventions. This makes PEDro useful when students are looking for evidence about intervention effectiveness and practice recommendations.
This is why RCTs are preferred over observational studies when the goal is to determine whether an intervention caused an outcome.
What is it because randomization helps control for clinical confounders?
Randomization helps control for confounders by making the treatment and control groups more comparable at baseline. Because participants are assigned to groups by chance, factors such as age, symptom severity, comorbidities, motivation, and other known or unknown characteristics are more likely to be balanced between groups
In a study of patients with low back pain, the reference group is patients with low fear-avoidance beliefs. Patients with high fear-avoidance beliefs have an odds ratio of 2.4 for persistent disability. Because this value is greater than 1, this is the direction of the odds.
What are increased odds of persistent disability?
An odds ratio compares the odds of an outcome between two groups. An OR greater than 1 indicates increased odds of the outcome in the comparison group relative to the reference group. An OR less than 1 indicates decreased odds, and an OR equal to 1 indicates no difference in odds. In this example, patients with high fear-avoidance beliefs had increased odds of persistent disability compared with patients with low fear-avoidance beliefs.
A student finds a journal article that appears relevant to a clinical question, but the journal source seems unfamiliar. Before trusting the article, the student should use these three quick checks to help evaluate whether the journal may be credible or potentially predatory.
What are checking Beall’s list, checking DOAJ, and checking JCR?
Three quick ways to screen for potentially predatory journals are to check Beall’s list for possible warnings, DOAJ to verify reputable open-access indexing, and JCR to confirm whether the journal is indexed and has a recognized impact factor. These tools support credibility checks but do not replace critical appraisal.