Equity-Focused Systematic Reviews: The PROGRESS-Plus Framework

Many systematic reviews report an intervention's overall average effect without examining whether that effect differs meaningfully across socially disadvantaged groups, potentially masking situations where an intervention works well on average but poorly, or not at all, for specific populations. The PROGRESS-Plus framework provides a structured way to build equity considerations into a systematic review's methodology deliberately, rather than as an afterthought.

What PROGRESS-Plus stands for

PROGRESS is an acronym covering Place of residence, Race/ethnicity/culture/language, Occupation, Gender/sex, Religion, Education, Socioeconomic status, and Social capital -- factors well established in health equity research as commonly associated with disparities in health outcomes and access to interventions. The "Plus" extends this to additional characteristics relevant to a specific review's context, such as age, disability, or sexual orientation, depending on what's genuinely relevant to the specific population and intervention being studied.

Why this framework rather than an ad hoc equity consideration

Without a structured framework, equity considerations in a systematic review risk being applied inconsistently or only when a reviewer happens to think of it for a specific study. PROGRESS-Plus provides a consistent checklist to apply across your whole review, from question framing through data extraction, ensuring equity-relevant characteristics are considered systematically rather than incidentally.

Building PROGRESS-Plus into your protocol

An equity-focused systematic review should specify at the protocol stage which PROGRESS-Plus characteristics are most relevant to the specific research question, and plan explicitly to extract data on these characteristics from included studies where reported, rather than deciding after screening is already complete which characteristics happen to have been reported and retrofitting an equity analysis around whatever data happens to be available.

Extracting equity-relevant data

Your extraction form should capture whether and how each included study reported on relevant PROGRESS-Plus characteristics within its population -- not just the overall study population description, but whether outcomes were reported separately by these characteristics, allowing an assessment of whether the intervention's effect actually varied across subgroups defined by disadvantage-related factors.

A common and important finding: equity reporting is often absent

A frequent, genuinely important finding in equity-focused systematic reviews is that many included primary studies simply did not report outcomes disaggregated by relevant equity characteristics at all, meaning the review cannot actually assess whether an intervention worked differently across disadvantaged groups, even when it wants to. Reporting this absence explicitly, as a specific finding about the primary evidence base's own limitations, is itself a valuable and increasingly expected contribution, not a failure of the review's own methodology.

PROGRESS-Plus and subgroup analysis

Where sufficient data does exist, PROGRESS-Plus characteristics become natural, pre-specifiable candidates for subgroup analysis or meta-regression, following the same statistical discipline that applies to any subgroup analysis -- pre-specified in the protocol, interpreted with appropriate caution given each subgroup's more limited statistical power, and reported using a formal interaction test rather than simply comparing separate significance tests across subgroups.

Reporting using PRISMA-Equity

PRISMA-Equity is an extension providing specific reporting guidance for equity-focused systematic reviews, expecting explicit reporting of which PROGRESS-Plus characteristics were considered, how equity was integrated into the review's question and methods, and what the findings suggest about differential effects or evidence gaps across disadvantaged populations specifically.

Equity considerations beyond just outcomes

Beyond whether an intervention's effect differs across PROGRESS-Plus characteristics, an equity-focused review can also examine whether the included studies themselves adequately represent disadvantaged populations in the first place -- a body of evidence drawn predominantly from advantaged populations has a genuine equity-relevant limitation worth naming explicitly, even before considering whether effects differ across subgroups within that already-skewed evidence base.

Why this matters beyond academic completeness

An intervention shown to work well on average, but only really studied in and effective for a relatively advantaged population, may be recommended for widespread implementation in a way that inadvertently widens rather than narrows existing health disparities. Systematically checking for this possibility, rather than assuming an average effect applies uniformly across all populations, is a genuine methodological improvement with real practical stakes for how systematic review findings eventually get used.

PROGRESS-Plus and grant or funding applications

Funders increasingly expect equity considerations to be addressed explicitly in systematic review proposals, and demonstrating a planned PROGRESS-Plus framework from the protocol stage, rather than adding equity language only in the discussion of a completed review, signals a genuine, structurally embedded commitment to this consideration rather than a rhetorical addition applied after the fact. Reviewers evaluating funding proposals increasingly look specifically for this kind of structural commitment, and a proposal that names PROGRESS-Plus explicitly and describes exactly how it will shape data extraction tends to read as considerably more concrete and credible than a general statement of intent to consider equity. Building PROGRESS-Plus into your project from the earliest planning conversations, rather than retrofitting equity language into an already largely designed protocol, tends to produce a more genuinely integrated final review than an equity consideration added as a late, somewhat disconnected addition to an otherwise already-finalized plan. This distinction between genuine structural integration and a late addition is one funders and methodologically sophisticated readers alike are increasingly attuned to, making the earlier, more deliberate approach the clearly more credible and more defensible one. Equity-focused methodology, done well, is ultimately less about adding an additional analytical step to an existing review template and more about genuinely reconsidering, from the ground up, whose evidence and whose outcomes a review is actually built to represent. That reframing, once genuinely adopted, changes what kinds of questions a review becomes capable of answering well, and for whom its conclusions genuinely apply. Pursuing that shift deliberately, project by project, is what ultimately moves an entire field toward more genuinely equitable evidence synthesis over the longer term, one carefully and thoughtfully conducted review at a time, together, with every team bringing this same deliberate attention to whose evidence and whose outcomes their own work actually represents. That reframing, once genuinely adopted, changes not just how a review is conducted but what kinds of questions it becomes capable of answering well. That shift is worth pursuing deliberately, not left to happen only by chance.