Synthesis
Part of entering the scholarly conversation is synthesizing and critiquing the research that’s gone on before, and judging levels of evidence.
Primary
In Module 1 we looked at scholarly articles and how to tell if something is an original primary, or empirical,study. As we go on, you'll learn to critique these original studies. However, there are also different types of scholarly articles, especially in the health fields, that present stronger or weaker levels of evidence. Randomized controlled trials are the highest level of evidence for original, primary studies.
Secondary
However, a single study won’t tell you everything you need to know about your research question, but seeing what a number of studies’ findings have said will give your an overview of findings so far. Though primary articles represent the latest research, secondary sources - sources that compile, examine, and critique primary articles - can not only provide a more understandable overview of the state of research on a question (including pointing you toward studies that support or refute your hypothesis and providing further references to follow up on in the bibliography), but also offer stronger evidence that's stood the test of time. Secondary sources include literature reviews (or review articles) and of these, systematic reviews and meta-analyses represent the highest levels of evidence. Because of this, the Wikipedia medicine portal suggests citing these.
Tertiary
The diabetes Wikipedia article, as well as the ones you find in subject encyclopedias like Access Science, are tertiary sources - sources that condense a lot of previous primary and secondary research into an easily understandable format. Other kinds of tertiary sources are the topics in Medline Plus, your textbook, or practice guidelines for doctors. These are good to start with, especially if you have no background in a subject, since they are often more easily understandable and can point you toward primary and secondary sources for more in-depth reading.
Types of health studies
from Vox.com
VIDEO: Primary, Secondary, and Tertiary Sources in the Health Sciences
Evidence-Based Medicine
Not all scientific studies are created equal! Study design can impact the strength and quality of evidence that a study holds. This 'Evidence Pyramid' depicts the levels of evidence provided by different types of studies and information. The wide base of the pyramid indicates that there are many editorials and expert opinions, but that they provide the weakest evidence to inform policy and decision-making. There are many fewer systematic reviews on a topic, but these represent the pinnacle of research evidence.
Check Your Understanding
Return to your course site, read the two articles under Module 4 and answer the questions in Library Activity 5a.
ACTIVITY: Evidence-Based Practice (optional, advanced)
Planning on a career in medicine or the health sciences? Want to know more about evidence-based medicine? Complete the following optional tutorial.
