Translating Evidence Into Practice: Writing the Synthesis of Evidence for Clinical Projects

The synthesis of evidence is the section of the DNP project that does for clinical scholarship what the literature review does for the traditional dissertation — and it is the section that DNP authors most consistently conflate with the literature review, to the detriment of both. Understanding the distinction is not a pedantic exercise. It is the difference between a document that demonstrates doctoral-level clinical scholarship and one that demonstrates advanced familiarity with the literature without making the move that the DNP degree requires.

A literature review surveys the existing research on a topic, identifies patterns and gaps, and positions the current study in relation to what is known. A synthesis of evidence evaluates the existing research on a specific clinical question, grades the quality and strength of that evidence, and builds an evidence-based argument for a specific practice intervention. The orientation is different, the product is different, and the standards by which each is evaluated are different.

The evidence hierarchy. Clinical evidence exists on a hierarchy of strength, from systematic reviews and meta-analyses at the top through randomized controlled trials, cohort studies, case-control studies, descriptive studies, and expert opinion at the lower levels. The synthesis of evidence should characterize each source by its level of evidence and should note what the level implies for the confidence with which the evidence supports the proposed intervention. Authors who cite clinical sources without acknowledging their position in the evidence hierarchy are producing a synthesis that a rigorous clinical reviewer will find incomplete.

Evidence grading tools. Many DNP programs require authors to use a specific evidence grading tool — the Johns Hopkins Nursing Evidence-Based Practice model, the GRADE framework, or a similar system — to evaluate and present the evidence. If the program specifies a tool, the synthesis should use it explicitly and consistently, with the grading results presented in an evidence table that accompanies the narrative synthesis. Authors who are unaware of the required tool, or who use a different tool from the one their program specifies, are creating a compliance problem that is straightforward to correct early and disruptive to correct late.

The evidence table. The evidence table is a structured summary of the sources reviewed, typically organized by source type or evidence level, with columns for the citation, the study design, the sample, the key findings, the level of evidence, and the quality rating. The evidence table is not a replacement for the narrative synthesis — it is a companion to it. The narrative synthesis builds the argument; the evidence table provides the systematic documentation of the evidence base that supports the argument.

The argument from evidence. The synthesis of evidence should conclude with an explicit argument: given the evidence reviewed, the proposed intervention is supported at a specified level of confidence for a specified population in a specified clinical setting. This conclusion should be specific enough to be evaluated — not "the evidence supports improved hand hygiene practices" but "the evidence at Level II-III supports the implementation of a structured nurse-led hand hygiene monitoring program in acute care settings as an effective intervention for reducing hospital-acquired infection rates." The specificity is what makes the document clinically useful rather than academically interesting.

The synthesis of evidence is where the DNP author demonstrates the capacity that the degree is designed to develop: the ability to evaluate clinical evidence critically, to distinguish strong evidence from weak evidence, and to build a coherent argument for a specific practice change on the basis of what the evidence actually supports. That capacity is worth demonstrating clearly.