Types of Research: Primary Vs Secondary

What is a primary source?

A primary source is a document or record which reports a study, experiment, event or other phenomenon firsthand. Primary sources are usually written by the person(s) who did the research, conducted the study, ran the experiment, or witnessed the event.

Primary Sources include:

• pilot/prospective studies

• cohort studies

• survey research

• case studies

• qualitative studies

• clinical trials and randomized clinical trials/RCTs

• double blind method

• dissertation or thesis

Example from CINAHL:

Hormone therapy and venous thromboembolism among postmenopausal women: impact of the route of estrogen administration and progestogens: the esther study. Canonico M; Oger E; Plu-Bureau G; Conard J; Meyer G; Levesque H; Trillot N; Barrellier MT; Wahl D; Emmerich J; et al.; Estrogen and Thromboembolism Risk (ESTHER) Study Group; Circulation, 2007 Feb 20; 115 (7): 840-5 (journal article - clinical trial, research)

Abstract:  BACKGROUND: Oral estrogen therapy increases the risk of venous thromboembolism (VTE) in postmenopausal women. Transdermal estrogen may be safer. However, currently available data have limited the ability to investigate the wide variety of types of progestogen. METHODS AND RESULTS: We performed a multicenter case-control study of VTE among postmenopausal women 45 to 70 years of age between 1999 and 2005 in France. We recruited 271 consecutive cases with a first documented episode of idiopathic VTE (208 hospital cases, 63 outpatient cases) and 610 controls (426 hospital controls, 184 community controls) matched for center, age, and admission date. After adjustment for potential confounding factors, odds ratios (ORs) for VTE in current users of oral and transdermal estrogen compared with nonusers were 4.2 (95% CI, 1.5 to 11.6) and 0.9 (95% CI, 0.4 to 2.1), respectively. There was no significant association of VTE with micronized progesterone and pregnane derivatives (OR, 0.7; 95% CI, 0.3 to 1.9 and OR, 0.9; 95% CI, 0.4 to 2.3, respectively). In contrast, norpregnane derivatives were associated with a 4-fold-increased VTE risk (OR, 3.9; 95% CI, 1.5 to 10.0). CONCLUSIONS:Oral but not transdermal estrogen is associated with an increased VTE risk. In addition, our data suggest that norpregnane derivatives may be thrombogenic, whereas micronized progesterone and pregnane derivatives appear safe with respect to thrombotic risk. If confirmed, these findings could benefit women in the management of their menopausal symptoms with respect to the VTE risk associated with oral estrogen and use of progestogens.

Subjects: Hormone Replacement Therapy; Thromboembolism; Venous Thrombosis; Venous Thromboembolism; Aged: 65+ years; Middle Aged: 45-64 years; Female

Recommended Databases:

Finding Primary Sources on Cinahl: Under Publication Type, select Clinical Trial and Randomized Clinical Trial. (Hold down the CTRL key to select multiple items in the list)

Finding Primary Sources on Medline: Under Publication Type, select Clinical Trial, Controlled Clinical Trial, and Randomized Clinical Trial. (Hold down the CTRL key to select multiple items in the list)

Finding Primary Sources on PubMed: After conducting your search, check the boxes for Clinical Trial, Controlled Clinical Trial, and/or Randomized Clinical Trial under Article Type in the left sidebar.