Evidence-Based Practice: Sources, PICO Framework, and Evidence Levels

This paper provides an overview of Evidence-Based Practice (EBP) in healthcare. It explores various sources of evidence, including online resources, print journals, and people, emphasizing the importance of quantitative research and randomized controlled trials. The paper discusses the PICO framework for formulating answerable questions and provides examples related to deep vein thrombosis and cardiovascular disease. Different levels of evidence for therapeutic studies are presented, highlighting the significance of high-quality evidence from research summaries and randomized controlled trials. The paper also examines different study designs, such as cohort and case-control studies, and their relevance to specific EBP questions. Finally, it categorizes evidence into primary and secondary research, emphasizing the importance of scientific methods in determining the quality of evidence.

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Evidence-Based Practice
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EVIDENCE-BASED PRACTICE
Evidence in evidence-based practice acts as proof and basis for rationality in support
or withdrawal of certain practices. The word evidence has been used to coin various
permutations with the trending one being evidence-based practice in healthcare to determine
what works and what does not (Rycroft-Malone et al., 2004). There are various sources of
evidence in EBP, but what counts is that the evidence has undergone adequate scrutiny.
Sources of evidence are reviewed based on their history and applicability, resulting in the
high regard for quantitative research, and consideration of randomized controlled trials as the
gold standards. Quantitative research ranks high in the hierarchy of evidence as it provides
measurable facts that are not based on subjective opinions as is the case with expert opinions
and analysis of cases that rank low in the hierarchy. Quantitative research is guided by
evidence-based questions whose formulation should be done meticulously.
There are various sources of evidence. First, there are online sources, which include
general and specialized search engines, electronic journals and books, subject gateways, and
websites, which include websites from professional organizations. Also, there are print
journals and books. People are also a source of evidence, and they are mainly useful in
qualitative research. Again, the media, including the TV, newspapers, and radio, are another
source, and lastly, libraries are useful sources of evidence (Public Health Action Support
Team [PHAST], 2017). Finding the best sources of evidence is dependent on the type of
question and research study where different research studies are given different hierarchies as
discussed later in this paper.
Identifying answerable questions that meet the SMART criteria is paramount in
addressing real-world problems. The PICO framework was established to help in the
formulation of relevant and well-structured questions that can help to retrieve meaningful and
useful information (Davis, 2011). The PICO framework was developed by Richardson and
his colleagues in 1995 with the aim to segment a clinical question into keywords that can be

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easily researched. The mnemonic refers to the patient or problem in reference to the patients
and their health conditions, the intervention to be considered. A comparison of the
intervention, and the desired outcomes.
In reference to deep vein thrombosis, a middle-aged female planning to travel through
air mode might be seeking ways of reducing its risk. Thereby, an evidence-based question
using the PICO framework that can be formulated based on such a scenario would be:
For an overweight middle-aged female, would compression stockings compare to in-flight
exercises prevent deep vein thrombosis?
In the question above, the patient or problem (P) is the overweight middle-aged female, the
intervention (I) are the compression stockings, a comparison (C) are in-flight exercise and the
outcome (O) is deep vein thrombosis.
The PICO framework is commonly used in clinical fields, though there are other
frameworks, as discussed by Davies (2011), but do not form the basis for the development of
this paper. Also, in another scenario, a clinician is wondering whether to improve the current
conventional care to improve the heart health of his patients. As a result, using the PICO, the
following EBP question would be formulated:
Among sedentary patients, does integration of a physical activity regimen and diet compared
to conventional care reduce the incidence of cardiovascular disease?
P is sedentary patients, I refers to combined physical activity regimen and diet, C is
conventional care while O is cardiovascular disease.
The best evidence to answer the two questions would include journals containing
articles that adopt research methods comparing the efficacy of the two treatment options.
Different levels of evidence have been designed depending on the dimension of health by
different health organizations, as indicated by Burns Burns, Rohrich, and Chung (2011).

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However, in this current paper, the levels of evidence for therapeutic studies will suffice as
indicated in the figure below.
Figure 1: Levels of Evidence for Therapeutic Studies (Center for Evidence-Based Medicine
cited in Burns et al., 2011)
The best sources of evidence to answer the two questions based on the hierarchies of
evidence would include those in levels 1because the two studies require the use of two study
samples at the same time. The other types of evidence as indicated in the table are useful for
questions that imply the use of one study sample. There are times when researchers and
clinicians seek to establish the cause of certain ailment by tracking exposure to the agent. In
such cases, the following question would be used as a guide:
Among individuals aged between 30 and 35 years, does cigarette smoke compared to normal
environment cause lung and throat cancer?
Cohort studies are longitudinal, and the subjects are followed over a long time to
determine what happens when the individuals are continually exposed to the suspected
disease-causing agent. Cohort studies are observational and most effective for detecting risk
factors. Case-control studies are also observational and even though similar to a cohort, they

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are retrospective while cohort studies are prospective. Thereby, the cohort ranks higher
because they are not likely to be affected by recall bias which affects the quality of case-
control studies. The question to guide case-control studies would be:
Among individuals with Guillain-Barré was exposure to Aedes aegypti bite or other mosquito
bites cause Zika virus?
Thereby, in reference to the formulated questions above, it is evident that there is a
strong link between the kind of EBP question and the study design used to answer the
question. Even though well-conducted RCTs and their reviews rank high in the hierarchy of
evidence, it is apparent that some questions warrant the use of other studies in the lower ranks
because RCT is not applicable, For example, in the last question, it is not plausible to
exposure individuals to mosquito bites. Thereby, despite the ranking, the best sources of
evidence for a particular EBP question should factor in the method used.
High-quality evidence includes that from research summaries, systematic reviews,
and randomized controlled trials. Evidence from such sources is deemed to be high-quality
evidence while evidence from expert opinions is of low quality due to lack of scientific
procedure in its collation. These sources can be broadly categorized as primary and secondary
research. Primary research is research that has been developed through the collection of
original data while in secondary research, original data is lacking (Gratton & Jones, 2010).
Nonetheless, secondary research forms a basic component of all research projects, including
primary research as it helps in determining the researches that have been conducted in
previous times to identify prevailing gaps.
Figure 1 above indicates the different types of evidence based on their quality. The
quality is dependent on the kind of methodology used, and since randomized controlled trials
are the gold standards, a collective review of a number of them prevails as the highest quality
of evidence and the rest follow as seen on the figure above. Also, as seen from the table,

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primary research forms the basis for high-quality evidence as opposed to secondary research
because in the latter, the rigor and use of scientific methods is not ascertained.

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References
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Gratton, C., & Jones, I. (2010). Research Methods for Sports Studies (2nd ed.). New York,
NY: Routledge.
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(2004). Nursing and Health Car Management and Policy: What Counts as Evidence
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