DEN 213W: Community Dental Health

What is a research article?

Empirical research articles report research based on actual observations or experiments. This research may use quantitative or qualitative methods. Quantitative research seeks to make deductions based on numerical data. Qualitative research analyzes mostly non-numerical sources such as observations, interviews and records. Abstracts of research articles will typically mention some sort of study or test, a methodology, and the data collected. In addition to an abstract, research articles normally have these sections:

• Introduction, which may incorporate a literature review
• Methodology, detailing specifics of how the research was done
• Results, listing data and outcomes
• Conclusion
• References

What is a randomly controlled trial (RCT)?

Randomized controlled trials (RCT) are prospective studies that measure the effectiveness of a new intervention or treatment. Although no study is likely on its own to prove causality, randomization reduces bias and provides a rigorous tool to examine cause-effect relationships between an intervention and outcome. This is because the act of randomization balances participant characteristics (both observed and unobserved) between the groups allowing attribution of any differences in outcome to the study intervention. This is not possible with any other study design. RCTs include the following characteristics

• Concealment of allocation (no knowledge at time of recruitment of which group the subject will be assigned--control group or intervention group)
• Blinding when appropriate (participants and providers of treatment do not know what treatment each participant is receiving)
• Intention to treat (ITT) analysis (subjects analyzed in the groups to which they were randomized)

Source: Randomized control panels: the gold standard for effectiveness research

What is a systematic review?

A systematic review is defined as “a review of the evidence on a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant primary research, and to extract and analyze data from the studies that are included in the review.”  The methods used must be reproducible and transparent.

Source: Undertaking Systematic Reviews of Research on Effectiveness. CRD’s Guidance for those Carrying Out or Commissioning Reviews.

 Advantages

• Exhaustive review of the current literature and other sources (unpublished studies, ongoing research)
• Less costly to review prior studies than to create a new study
• Less time required than conducting a new study
• Results can be generalized and extrapolated into the general population more broadly than individual studies
• More reliable and accurate than individual studies
• Considered an evidence-based resource

Disadvantages

• Very time-consuming
• May not be easy to combine studies

What is a meta-analysis?

A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power. This conclusion is statistically stronger than the analysis of any single study, due to increased numbers of subjects, greater diversity among subjects, or accumulated effects and results.

 Advantages

• Greater statistical power
• Confirmatory data analysis
• Greater ability to extrapolate to general population affected
• Considered an evidence-based resource

Disadvantages

• Difficult and time consuming to identify appropriate studies
• Not all studies provide adequate data for inclusion and analysis
• Requires advanced statistical techniques
• Heterogeneity of study populations

Source: https://himmelfarb.gwu.edu/tutorials/studydesign101/metaanalyses.cfm

Further reading: Introduction to systematic review and meta analysis