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Evidence Based Practice: Primary & Secondary Sources

A guide to the fundamentals of Evidence Based Medicine.

What is a primary source?

"Primary sources are original materials/information on which other research is based. It includes journal articles of original research, conference papers, dissertations, technical reports, and patents. Primary sources are also sets of data, such as health statistics, which have been tabulated, but not interpreted."

-University of Minnesota Bio-Medical Library. (2010). Primary, secondary, and tertiary sources in the health sciences.

It's probably primary if... presents new research. Look for a description of methodology - did they create new data, or are they examining data generated by other people or groups?

...tries to address a specific question. Are the authors finding an answer, or providing an overview?

...contains "raw data". Does the article present information directly (ie. tables, graphs), or does it only describe the information collected?

It's probably secondary if... reviews data produced by others. Look for terminology such as "overview", "meta-analysis", or "literature review"

...provides a broad overview of a field. If it's not addressing a specific question, it is often a summary of work performed by others.

...provides a personal view. Editorials, analysis, responses to articles, and such - while these are often useful, they aren't presenting unbiased information that can be used by other parties without examination for bias.

Primary vs. Secondary Guidelines

If you'd like a refresher on what qualifies as a primary source, the American Journal of Nursing has provided guidelines as used by authors submitting to the journal.

Test your knowledge

Is it Primary?

Quiz #1

Title: Improving care of patients with diabetes and CKD: a pilot study for a cluster-randomized trial.

Author(s): Cort's-Sanabria L; Cabrera-Pivaral CE; Cueto-Manzano AM; Rojas-Campos E; Barragn G; Hernández-Anaya M; Martínez-Ramírez HR Affiliation: Unidad de Investigación Médica en Enfermedades Renales, Hospital de Especialidades, CMNO, IMSS, Belisario Domínguez No. 1000, Col. Independencia, Guadalajara, Mexico.

Source: American Journal of Kidney Diseases (AM J KIDNEY DIS), 2008 May; 51(5): 777-88

Publication Type: journal article

Abstract: BACKGROUND: Family physicians may have the main role in managing patients with type 2 diabetes mellitus with early nephropathy. It is therefore important to determine the clinical competence of family physicians in preserving renal function of patients. The aim of this study is to evaluate the effect of an educational intervention on family physicians' clinical competence and subsequently determine the impact on kidney function of their patients with type 2 diabetes mellitus. STUDY DESIGN: Pilot study for a cluster-randomized trial. SETTING & PARTICIPANTS: Primary health care units of the Mexican Institute of Social Security, Guadalajara, Mexico. The study group was composed of 21 family physicians from 1 unit and a control group of 19 family physicians from another unit. 46 patients treated by study physicians and 48 treated by control physicians also were evaluated...

Journal Subset: Biomedical; Blind Peer Reviewed; Editorial Board Reviewed; Expert Peer Reviewed; Online/Print; Peer Reviewed; USA

The article to which the citation above refers would be considered primary source material because [select one]:

a. It is a report of an original research study indicated by the methodology outlined in the abstract.

b. It is in The American Journal of Kidney Diseases.

c. The authors are Hispanic and the study takes place in Mexico.

Is it Secondary?

Quiz #2


Authors: Fargen, Jessica

Source: Prevention; Jun2008, Vol. 60 Issue 6, p34-34, 1/5p

Document Type: Article

Abstract: This article discusses research indicating that taking a cholesterol lowering statin pill daily can improve the health outlook for diabetes patients. It noted reduced numbers of heart attacks and strokes, whether or not those patients had already been diagnosed with vascular disease.

The article to which the citation above refers would be considered secondary source material because [select one]:
a. It is in magazine called Prevention.

b. It is a discussion of someone else's research as indicated in the abstract.

c. It is not a secondary source; it is primary.

What Have You Learned?

Quiz #3

Title: Effect of nasogastric tubes on incidence of aspiration.

Author(s): Leder SB; Suiter DM

Affiliation: Department of Surgery, Section of Otolaryngology, Yale University School of Medicine, New Haven, CT 06520-8041, USA.

Source: Archives of Physical Medicine & Rehabilitation (ARCH PHYS MED REHABIL), 2008 Apr; 89(4): 648-51 (16 ref)

Publication Type: journal article

Abstract: OBJECTIVE: To determine what effect, if any, a nasogastric (NG) tube has on occurrence of anterograde aspiration during objective evaluation of swallowing using both liquid and puree bolus consistencies. DESIGN: Prospective, consecutive. SETTING: Large, urban, tertiary care, teaching hospital. PARTICIPANTS: Referred sample of 1260 consecutively enrolled inpatients. Group 1 (n=630; 346 male, 284 female) had an NG tube and group 2 (n=630; 360 male, 270 female) did not have an NG tube at time of referral for dysphagia evaluation. INTERVENTION: Fiberoptic endoscopic evaluation of swallowing (FEES)...

Journal Subset: Allied Health; Double Blind Peer Reviewed; Editorial Board Reviewed; Expert Peer Reviewed; Online/Print; Peer Reviewed; USA


Title: Asian flus in ethnographic and political context: a biosocial approach.

Author(s): Kleinman AM; Bloom BR; Saich A; Mason KA; Aulino F

Affiliation: Department of Anthropology, Harvard University, Cambridge, MA

Source: Anthropology & Medicine (ANTHROPOL MED), 2008 Apr; 15(1): 1-5 (7 ref)

Publication Type: journal article - editorial

Abstract: This collection highlights some of the social, cultural, political and economic factors that must be considered in developing a biosocial approach to pandemic influenza control and prevention. To date, most discussions of the current spread of avian influenza and a predicted human influenza pandemic have lacked rigorous analysis of the local contexts in which flus arise and in which the effects of a pandemic would most strongly be felt...

Journal Subset: Biomedical; Online/Print; Peer Reviewed; UK & Ireland

How many of the literature types below accurately describe the article/citation above? (check all that apply)

Peer Reviewed

How many of the literature types below accurately describe the article/citation above? (check all that apply)

Peer Reviewed

Adapted with permission from the University of Southern Mississippi Library.