Original research articles are based on an experiment or study. The authors will report the purpose of the study, the research methodology, and results. This is a familiar structure for original research articles > IMRAD: introduction, methods, results, and discussion.
primary research article/source
primary literature article
empirical research article
In some cases, original research articles are simply labeled as "articles" in library databases.
In describing the purpose of their study, authors will present a mini literature review to discuss how previous research has led up to their original research project.
Review articles summarize or synthesize content from earlier published research and are useful for surveying the literature on a specific research area. Review articles can lead you to original research articles.
Narrative Review: a literature review that describes and discusses the state of the science of a specific topic or theme.
Systematic Review: a comprehensive review of all relevant studies on a particular topic/question. The systematic review is created by following an explicit methodology for identifying/selecting the studies to include and evaluating their results.
Meta-Analysis: the statistical procedure for combining data from multiple studies. This is usually but not always presented with a systematic review.
I M R A D (!)
I - Introduction
What's this study about? What population, or phenomenon, are we studying? Why are we studying it? What gaps in knowledge exist that make this study necessary?
M - Methods or Methodology
How will we answer the questions posed in the introduction? Who or what are we studying? What group (men, women, adults, children, lower economic class, middle economic class, upper economic class, et c.)? How will we study them: survey, experiment? How will we measure our results? How will we measure our results -- what scales will we use?
R - Results
What were the results of all that measuring? This section of an empirical study journal article is likely to have a lot of tabular data: charts, tables, graphs, et c.
D - DISCUSSION
What's it all mean? What impact do the results have on the field or discipline? What gaps in knowledge have been answered?