Literature sources form the foundation of evidence-based nursing practice. When Nigerian nursing students and researchers begin a study or a quality improvement project, they must gather reliable data to support their claims. Literature sources are broadly categorized into three tiers based on how close the author is to the original research or event: primary, secondary, and tertiary. Understanding these tiers helps the nurse researcher build a logical, credible argument and avoid relying on weak or biased information.
A primary source is written by the person who actually conducted the research or lived the experience. In nursing, these include randomized controlled trials, qualitative interviews, observational studies, and clinical case reports. They contain raw data, detailed methodologies, and firsthand accounts. When you read a journal article where the authors state they administered a questionnaire to postpartum mothers in Lagos, you are reading a primary source.
Secondary sources interpret, discuss, or summarize primary literature. Instead of collecting raw data from patients, the authors of secondary sources review multiple primary studies to find patterns or conclusions.
Tertiary sources distill or index primary and secondary sources into broad overviews. They provide quick background facts rather than deep analysis. Common examples include nursing textbooks, medical dictionaries, encyclopedias, and bibliographic indexes like PubMed or CINAHL. While tertiary sources are excellent for getting background information on a new disease condition or nursing theory, they should not form the core reference base for an advanced research paper.
Evaluating where information is published helps determine its reliability.
| Feature | Peer-Reviewed Journals | Grey Literature |
|---|---|---|
| Definition | Articles evaluated by independent experts before publication | Materials produced outside traditional commercial publishing |
| Examples | Original research in professional nursing journals | Government reports, conference abstracts, policy briefs |
| Quality Control | High scrutiny through blind review | Varies widely; often lacks formal editorial review |
| Accessibility | Usually requires subscription or library access | Often freely available online |
Grey literature can provide valuable local data, such as a Nigerian Ministry of Health bulletin, but requires extra caution regarding bias and methodology.
Finding the right literature requires knowing where to look and how to ask. Major electronic databases for nursing include CINAHL, PubMed, MEDLINE, and Cochrane Library. To retrieve precise results instead of thousands of irrelevant articles, nurses use search strategies like Boolean operators (AND, OR, NOT) and medical subject headings. For instance, searching for "nursing" AND "malaria" narrows down results to studies intersecting both concepts.
Not all published information is trustworthy. When selecting literature, nurses must critically appraise the authority of the author, the currency of the information, and the objectivity of the publisher. A study published twenty years ago on intravenous cannulation techniques may be outdated due to new safety equipment and guidelines. Always verify whether the authors have relevant clinical expertise and whether funding sources introduce conflicts of interest.