EBP Models Compared: Iowa vs Johns Hopkins vs ACE Star

Most nursing programs require an evidence-based practice project to be structured around a named EBP model, but rarely explain why one model was chosen over another, or how the three most common frameworks actually differ in practice. This guide compares the Iowa Model, the Johns Hopkins Evidence-Based Practice Model, and the ACE Star Model side by side, so you understand the model your program assigned rather than just following its steps mechanically.

The Iowa Model of Evidence-Based Practice

The Iowa Model organizes the EBP process around "triggers" - either problem-focused triggers (a clinical problem prompting the question) or knowledge-focused triggers (new research prompting a practice review). After identifying a trigger, the model moves through forming a team, gathering and critiquing evidence, and - distinctively - a formal piloting stage before any organization-wide change is implemented. This piloting step is one of the Iowa Model's defining features: it explicitly separates "try this on a small scale" from "adopt this everywhere," which makes it a strong fit for projects where organizational buy-in for a full rollout is uncertain.

Best fit for: Projects starting from a specific clinical trigger, where a genuine small-scale pilot before wider implementation is feasible and valuable.

The Johns Hopkins Evidence-Based Practice Model

The Johns Hopkins model divides the EBP process into three distinct phases, commonly summarized as PET: Practice question, Evidence, and Translation. The practice question phase closely resembles PICOT question development. The evidence phase involves a structured literature search and a formal evidence-rating system, using a defined hierarchy to grade the strength and quality of each source. The translation phase focuses on creating an action plan, implementing it, and evaluating outcomes. Johns Hopkins is particularly known for the rigor of its evidence-appraisal tools, which many programs use even when the rest of the project follows a different model.

Best fit for: Projects where the literature search and evidence appraisal is the most complex part of the work, or where your program specifically wants a formal evidence-grading rubric applied.

The ACE Star Model of Knowledge Transformation

The ACE Star Model frames EBP as a five-point cycle: Discovery (new research knowledge), Evidence Summary (synthesizing that research, often through systematic review methodology), Translation into practice recommendations, Integration into practice, and Evaluation of the outcome. Its distinguishing feature is treating evidence synthesis as a formal step in its own right, closely resembling systematic review methodology, rather than folding it into a broader "gather evidence" phase the way the other two models do.

Best fit for: Projects where the literature synthesis itself is substantial enough to resemble a mini systematic review, and where your program wants that synthesis treated as a distinct, weighted phase of the project.

Choosing Between Them When You Have a Choice

If your program allows you to select a model rather than assigning one, consider what your project actually emphasizes. If piloting a change on a small scale before wider rollout is central to your plan, the Iowa Model's built-in pilot phase fits naturally. If your project depends heavily on rigorous evidence grading, Johns Hopkins offers the most structured appraisal tools. If your literature synthesis is extensive enough to function almost as its own systematic review, ACE Star's dedicated Evidence Summary phase matches that emphasis most directly.

Beyond the Big Three: Other Models You Might Encounter

While Iowa, Johns Hopkins, and ACE Star are the models most commonly assigned, some programs use others worth recognizing if you encounter them. The Stetler Model emphasizes individual practitioner application of evidence rather than organizational change, making it more common in advanced practice contexts than unit-level projects. The Rosswurm and Larrabee Model closely resembles Iowa's structure but places extra emphasis on establishing organizational fit before implementation. If your program assigns one of these less common models, the same underlying logic applies: identify its distinguishing phase or emphasis, and let that shape which parts of your project you develop in the most depth.

Justifying Your Model Choice in a Proposal

If your program allows you to choose a model, most proposal templates ask you to briefly justify that choice rather than simply naming it. A weak justification just states the model's name and general purpose. A stronger justification connects specific features of the model to specific features of your project - for example, explicitly noting that your project includes a planned small-scale pilot before wider rollout, and that this is exactly what the Iowa Model's structure was built to support, rather than retrofitting the model's steps onto a project designed without it in mind from the start.

A Common Mistake: Mixing Models Without Realizing It

A frequent issue in student EBP write-ups is borrowing terminology from one model while structurally following another - for example, using Iowa Model triggers language but Johns Hopkins' PET phase structure. This usually happens when a student reads about multiple models before settling on one. Once you choose a model, keep its specific terminology and phase structure consistent throughout the write-up, since committees reviewing your work will be checking for that internal consistency.

How CampusScribe Supports EBP Model Selection and Application

CampusScribe's subject-specialist editors help nursing students apply whichever EBP model their program requires consistently and correctly, and can advise on which model best fits a project when you have a genuine choice.

If you would like feedback on how your EBP model is being applied in your project, get in touch with our editing team.

Final Thoughts

All three models cover the same fundamental EBP process - question, evidence, translation - but structure and emphasize it differently. Confirm which one your program requires early, keep its specific terminology consistent throughout your project, and let its particular strengths guide which parts of your project get the most attention.

Regardless of which model your project ultimately uses, the underlying discipline is the same: a clearly defined trigger or question, systematic evidence gathering, honest appraisal of what that evidence shows, and a realistic plan for translating it into practice. Understanding these frameworks well enough to defend your choice in a proposal meeting is, in the end, more valuable than memorizing any single model's steps by rote.

From choosing a topic to polishing a final draft, CampusScribe's subject-specialist editors and coaches help with dissertations, capstone projects, presentations, and more - whether you need topic guidance, structural feedback, or a final edit before your deadline.