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Research Methods & Studies

What are Research Methods?

Research methods are a set of standardized processes on how to conduct research. Though more common within the sciences, research methods are also utilized within other fields such as business, healthcare services, and education. The type of research method chosen is typically dependent on a number of factors, such as:

  • The nature of the problem being addressed
  • The theoretical stance and preferred methods of the researcher or research team
  • The time and money available
  • The type of research and evidence that most likely meets the preferences of and make the most impact with the research's sponsors or audience

In turn, the type of method chosen will determine whether the research will have an inductive or deductive approach. An inductive approach to research focuses on observing phenomena and then arriving at a theoretical explanation for that behavior. A deductive approach works in reverse, beginning first with a theory and then working to find evidence that either supports or refutes it. That said, some research methods can make use of both approaches.

There are two major types of empirical research study (i.e. research based on data of an observed or measured phenomena): qualitative and quantitative

Importance of Critical Appraisal

Critical appraisal is a systematic process used to identify the strengths and weaknesses of a research article in order to assess the usefulness and validity of research findings. The most important components of a critical appraisal are an evaluation of the appropriateness of the study design for the research question. Please read more: Clinical Appraisal of Clinical Research, published in the Journal of Clinical and Diagnostic Research


Bias can be defined as: ‘a systematic error, or deviation from the truth, in results or inferences.’

Publication (Reporting) Bias - "Studies with positive results (or drastic results) are greatly more represented & published in literature than studies with negative results, producing so-called publication bias." Underreporting of negative results introduces bias into meta-analysis (data with negative/results that don’t support the initial hypothesis often remain unpublished and therefore excluded from meta-analysis & larger scope of research).

  • Pharmaceutical companies often do not have the incentive to publish negative results of drug investigations. It is estimated that 60% of clinical trials with findings of inadequate drug efficacy or safety concerns remained unpublished.
  • Publication bias may lead to overestimating the effect of the intervention being examined in the meta-analysis. In order to ensure the reliability of a meta-analysis, one must systematically search for negative trials for inclusion.

Time-Lag Bias - "Occurs when the speed of publication depends on the direction and strength of the trial results. For example, studies with significant results may be published earlier than those with non-significant results"

Retrieval Bias - "This bias refers to a potential distortion of the findings of a meta-analysis due to the overlooking or exclusion of relevant studies that merit inclusion. It is critically important to search a variety of different databases."

  • Researchers should be particularly attentive to carefully choosing search terms. The appropriate use of Subject Headings, keywords and Boolean search strings can help maximize the retrieval of relevant articles.

Location Bias - "Occurs when the nature and direction of results are associated with publication in journals with different ease of access of levels or indexing in standard databases." This is related to retrieval bias. 

Multiple (Duplicate) Publication Bias - "Investigators may report the results of their study across multiple publications - Evidence suggests that studies with statistically significant results or larger treatment effects are more likely to lead to multiple publications (‘multiple (duplicate) publication bias’), which makes it more likely that they will be located and included in a meta-analysis."

Language Bias - "Language bias is closely related with retrieval bias. It refers to a potential distortion of the results of a meta-analysis due to a failure to identify relevant study findings published in languages other than English."

Heterogeneity/Homogeneity - Refers to the variation in study outcomes between studies. Heterogeneity refers to multiple studies having too great a variation in their results and making it difficult to compare & analyze the studies and draw any useful conclusions; performing analyses may not be feasible. Homogeneity refers to having multiple studies with similar results. 

Funding (Sponsorship) Bias - "Industry-sponsored studies tend to be biased in favor of the sponsor’s products. Several studies have explored this issue, documenting how the funding source can influence the design, conduct, and publication of research. Although more difficult to define, sponsorship can also influence the research agenda, namely the initial step in conducting research, during which the research questions are chosen and framed."

Novelty Bias - "is the tendency for an intervention to appear better when it is new. It is also known as the ‘novel agent effects’ or ‘fading of reported effectiveness’." 

Citation Bias"The number of times a study report is cited appears to be influenced by the nature and direction of its results. In a meta-analysis of 21 methodological studies, it was observed that articles with statistically significant results were cited 1.57 times the rate of articles with non-significant results . The study also found that articles with results in a positive direction (regardless of their statistical significance) were cited at 2.14 times the rate of articles with results in a negative direction. If positive studies are more likely to be cited, they may be more likely to be located, and thus more likely to be included in a systematic review."