DQA 2 : Describe the levels of evidence and provide an example of the type of practice change that could result from each.
Describing the hierarchy is the easy half. The graded half pairs each level with the kind of practice change it could actually justify, and those are not the same size of change.
Editorial process
Last reviewed · August 22, 2026
Each level licenses a different size of change
Two things are being asked and the second is the one that separates posts. Getting the hierarchy right matters, so state it in the form your course uses and be careful with the top: systematic reviews and meta-analyses of randomised controlled trials sit above single randomised trials, which sit above controlled trials without randomisation, then case-control and cohort studies, then systematic reviews of qualitative or descriptive studies, then single qualitative or descriptive studies, and finally expert opinion. Say what actually orders them, which is susceptibility to bias and confounding rather than effort or prestige, because that explains why a large observational study still ranks below a small randomised one. It is also worth noting that hierarchies rank designs rather than studies, so a badly conducted randomised trial can be worse evidence than a carefully conducted cohort, which is why grading systems such as GRADE assess quality separately from design.
The second half is where the thinking shows. Pair each level with the kind of practice change it could justify, and notice the scale differs. Level one evidence supports a change to a system-wide protocol or policy, because the effect is unlikely to be an artefact and applies beyond one setting: a national guideline changing a screening interval is the recognisable example. A single trial supports a pilot on one unit with evaluation built in. Cohort and case-control evidence supports a risk-assessment or surveillance change rather than a treatment change, because association is what that design establishes. Qualitative evidence supports a change to how care is delivered and experienced, such as redesigning a discharge conversation, which is exactly the kind of question a trial cannot answer well. Expert opinion supports a provisional local practice pending better evidence. Add the point most posts miss: the level constrains how confidently and how widely you may change practice, not whether change is allowed.
Likely learning objectives
- State the hierarchy of evidence accurately and in order.
- Explain that the ordering reflects susceptibility to bias.
- Match each level to the scale of practice change it can justify.
- Recognise what qualitative evidence is uniquely able to support.
Assignment instructions
Read the full question
Review every instruction before using the planning guidance that follows.
NRS 433 Topic 4 DQ 2 DQA 2 : Describe the levels of evidence and provide an example of the type of practice change that could result from each.
Turn the brief into deliverables
- 01The levels of evidence, in order and correctly grouped.
- 02The reason for the ordering.
- 03An example of a practice change for each level.
- 04A change matched to qualitative evidence specifically.
- 05A statement of how level constrains scope and confidence rather than permission.
The hierarchy, then a change matched to each level
The hierarchy, in order
State the levels from systematic review through to expert opinion.
What the assessor is likely looking for
Systematic reviews of trials distinguished from single trials.
What actually orders them
Explain susceptibility to bias and confounding as the ordering principle.
What the assessor is likely looking for
An explanation of why a large cohort ranks below a small trial.
Changes level one can justify
Give a protocol or policy change appropriate to the strongest evidence.
What the assessor is likely looking for
A change whose scope matches the evidence's generalisability.
Changes the middle levels justify
Match single trials and observational designs to pilots and risk assessment.
What the assessor is likely looking for
Association evidence tied to surveillance rather than to treatment.
What qualitative and expert evidence support
Show the delivery and experience changes qualitative work uniquely supports.
What the assessor is likely looking for
A change a trial could not have established.
Where the hierarchy and its grades are published
Recommended databases
- PubMed Central
- NCBI Bookshelf
- Cochrane Library
- GCU Library
Search sequence
- 1.Take the hierarchy from a published source rather than from memory.
- 2.Read how grading systems separate evidence quality from recommendation strength.
- 3.Find one guideline that cites its evidence level explicitly.
- 4.Look for a qualitative study that changed a care process.
Reference shortlist
These are authoritative starting points, not a ready-made bibliography. A qualified reviewer must confirm that each source fits the assignment and supports the claim beside which it is cited.
The hierarchy of evidence: levels and grades of recommendation
Indian Journal of Orthopaedics, via PubMed Central · 2010
The hierarchy of evidence with levels and grades of recommendation.
Evidence-Based Medicine
StatPearls, NCBI Bookshelf · 2024
Evidence-based medicine, for the three-part definition and where levels sit within it.
The PRISMA statement, for what a systematic review at the top of the hierarchy requires.
Unhealthy Alcohol Use in Adolescents and Adults: Screening and Behavioral Counseling Interventions
United States Preventive Services Task Force · 2018
A graded recommendation, as a worked example of evidence level driving practice.
Implementation strategies for large scale quality improvement initiatives in primary care settings: a qualitative assessment
BMC Primary Care · 2023
A qualitative implementation study, for the kind of change qualitative evidence supports.
Before you post to the Topic 4 forum
Common mistakes
- Listing the levels without saying what orders them.
- Giving the same size of practice change for every level.
- Treating qualitative evidence as weak rather than as answering different questions.
- Placing a large observational study above a randomised trial because of its size.
- Omitting expert opinion, which still governs a good deal of practice.
Submission checklist
- Is the hierarchy stated in the order your course uses?
- Have you explained the ordering by bias rather than by effort?
- Does each level get its own kind of change?
- Is the qualitative example about experience or delivery rather than effect?
- Have you said what the level constrains?
Use this guide to plan and review your own work. Follow your institution's rules and read Brinevia's academic-integrity policy.
Written by
Maren Caldwell
MSN, RN, CNE
Medical-surgical nursing, pharmacology and NCLEX preparation
Maren is a registered nurse with over 15 years of clinical and educational experience in medical-surgical nursing. She writes on NCLEX preparation, patient care fundamentals, pharmacology and evidence-based practice.
Reviewed by
Dr. Tessa Redmond
DNP, RN, CNE
Evidence-based practice and clinical education
Tessa is a doctorally-prepared nurse educator. She reviews Brinevia content for clinical accuracy and alignment with current evidence-based guidelines.