Yanfang Su ^1* Heather Bullock ² Michael Trisolini ³ Karen Emmons ⁴

• ¹ Department of Global Health, School of Public Health, University of Washington, Seattle, Washington, United States
• ² Department of Health Research Methods, Evidence & Impact, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
• ³ Northeastern University, Boston, Massachusetts, United States
• ⁴ Department of Social and Behavioral Sciences, School of Public Health, Harvard University, Boston, Massachusetts, United States

integration of legal epidemiology and IS (Lane and Stergachis); a measurement study on acceptability and feasibility of policy implementation strategies (Purtle et al.); one qualitative comparative case study on policy intermediaries (Bullock et al.); and one case study on food assistance policy implementation (Kenney et al.); one quantitative evaluation effective communication related to policy IS (Dodson et al.); one mixed-method study on inter-sector care for the homeless (Martins et al.); one design study on participatory development of a target policy profile (Means et al.). Reviewing the papers included in this Research Topic, we identified several themes salient to the future of policy IS. Policies include regulatory, promotional, and redistributive decisions and guidelines for implementing programs to achieve societal goals. 1 Lane and Stergachis addressed the importance of systematic collection and coding of laws to enable policy implementation analysis. It is notable to observe that a consensus was implicitly reached in the 12 manuscripts regarding the importance of the evidence base for policy and practice (EBPP). The working definition of policy IS in the 12 manuscripts aligns with the National Cancer Institute definition of policy IS. 2 However, from a policy perspective, research evidence is not the only input into policy decisions and that is why evidence-informed policies and practices (EIPP) was raised as a critical concept. 3 In public administration, policy implementation is defined as a deliberate, sanctioned change to public policy legitimized by a political authority, with an emphasis on changing the status quo and adapting to diverse contexts. 4 Scientific evidence is considered as one of multiple resources in implementation. Policy implementation strategies include information campaigns (Kenney et al.), licensing (Bera et al.), as well as others (e.g., contracting, subsidies, accreditation).Through literature review and synthesis, Tao et al. highlighted policy implementation strategies, including training, resource reallocation, and increased insurance coverage. Policy IS has distinctive challenges in different settings and contexts (e.g., global vs. domestic). Incorporating contextual contingencies is important to address the factors affecting policy IS. List et al. brought the concept of Global North (United States, Canada, and Western Europe) and Global South in the discussion of global policy implementation in decolonizing global health. They highlighted donors as the bridge and power to connect two types of partners and reflected on who produced the frameworks and whether it was reciprocal.In synthesizing scientific evidence, conceptual frameworks are crucial to cluster the findings and aggregate knowledge, with the potential of theorization. Health Triangular Policy Framework by O'Brien et al. (2020) was applied in the narrative review by Tao et al., with an emphasis on actor-relevant contexts, contents, and processes. 5 In survey-based studies with policymakers and implementers, low response rates are a general challenge. For example, Dodson et al. had a 4.5% response rate in a national survey of local officials. Nonetheless, the results from these studies shed light on policy implementation practice. Dodson et al. studied the strategies to deliver policy briefs to facilitate information dissemination to local policymakers. Their study found that the narrative policy briefs had the lowest score (42%) related to strength in reasoning. In contrast, usual-care and risk-framing brief types had significantly higher scores to reflect strong reasoning (59% and 52%, respectively). This Research Topic collected diverse studies to learn for action. Bullock Challenges in policy IS include the complexity of developing overarching theories that address diverse contexts and evolving implementation partners. Contextual analysis often lacks direct causal links to outcomes, while randomized trials are difficult due to the nature and scale of policy implementation. Other useful policy IS methods include legal epidemiology (Lane and Stergachis) and coincidence analysis. 7 Additionally, measuring outcomes across macro, meso, and micro levels, accounting for both intended and unintended effects, remains complex.A limitation of this Research Topic is that all of the manuscripts are in health and related domains such as food and nutrition (Kenney et al. and Smith et al.) and housing instability (Martins et al.). We anticipate that future Research Topics will cover other social policies, such as unemployment, poverty, education, and LGBTQIA+ marriage. We also anticipate future studies on systematic reviews to understand the overarching landscape of policy implementation, modeling studies to predict policy impacts, costing methods for use in policy implementation, and others.