Our recent publication titled, ‘Recurring patterns of SDG interlinkages and how they can advance the 2030 Agenda,’ helps to answer this question based on a review and synthesis of the most up-to-date scientific literature on SDG interlinkages. Understanding how the SDGs interact in terms of synergies and trade-offs can guide decision making and priority setting in several ways. It can show where to invest to maximize progress on the 2030 Agenda as a whole, by pointing to highly synergistic goals. It can also show areas where the SDGs conflict, and decision makers therefore need to make critical choices or implement compensatory measures. Finally, it can improve alignment between SDG strategies, national development plans, and parallel policy agendas such as the Paris Agreement on climate change, leading to a more coherent and effective use of resources.

The scientific literature on SDG interlinkages has grown rapidly in recent years and has broad reach. Getting a handle on this potentially useful body of knowledge is tough. Existing analyses range from local-scale case studies, focusing on how a few SDGs are related, to global or non-place-specific assessments of interlinkages between the full set of Goals.

In our review of this research, we focus on the latter: global or non-place-specific interlinkages between all SDGs. And where previous reviews and meta-analyses have focused largely on methods and approaches, our review, in contrast, synthesizes knowledge on the relationships between the SDGs to identify any recurring patterns and overarching lessons that emerge from the literature.

The interlinkages between the SDGs are often argued to be context-specific, which implies that the relationships between the SDGs are not generalizable. However, our results indicate that certain SDGs are more likely to create synergies and trade-offs than others, across contexts.

Opportunities ahead

In 2024, several meetings will take place where there are opportunities to spur SDG action, such as the UN Multi-stakeholder Forum on Science, Technology and Innovation for the SDGs (STI Forum) 2024, UN Regional Forums on Sustainable Development (RFSDs), and the Summit of the Future. Recurring patterns of SDG interlinkages can inform the discussions leading up to these meetings, supporting efforts to localize the 2030 Agenda and serving as a basis for further analysis.

For example, decision makers should pay attention to the subset of Goals that strongly promote other SDGs. As our synthesis shows, progress on education (SDG 4), water and sanitation (SDG 6), and partnerships (SDG 17) have the potential to broadly drive progress on the 2030 Agenda as a whole. These Goals also seem to represent “safe” investments – in general – as progress in these areas does not seem to generate negative impacts or unintended consequences in other areas.

On the other hand, some targets related to food security (SDG 2), decent work and economic growth (SDG 8), and sustainable cities and communities (SDG 11) seem more likely to involve trade-offs that negatively affect the possibilities of achieving other Goals. This means that these Goals need to be treated with care and that action needs to be taken to mitigate trade-offs where possible. The environmental SDGs (14 on life below water and 15 on life on land) are also associated with trade-offs, but in the sense that they are the Goals that are most negatively affected by actions to promote other SDGs.

Recurring patterns of SDG interlinkages can also be useful to researchers as a baseline against which to compare their findings. For example, comparing findings at the local or national levels to these interlinkage patterns allows for an in-depth analysis of reasons for potential similarities and differences. In this way, one can better understand the underlying conditions and drivers that generate SDG synergies and trade-offs.

We strongly believe that the growing evidence base of SDG interlinkages can help accelerate SDG progress. However, our review and synthesis also point to several uncertainties, knowledge gaps, and unexpected findings, which underscore the need for further research and better alignment between research and policy needs in the second half of SDG implementation. We specifically stress three focus areas for further research:

• Focus on clarifying how certain SDGs drive or hinder progress. Important perspectives, explanations, and critical discussion are missing from the global or non-place-specific assessments of SDG interlinkages. This includes the need to better map the synergies arising from reducing inequalities (SDG 10), achieving sustainable cities and communities (SDG 11), and protecting marine and terrestrial ecosystems (SDGs 14 and 15). It also involves better explaining trade-offs that have been associated with reductions in inequalities (SDG 10) and efforts to achieve sustainable consumption and production (SDG 12).
• Dig into the complexity. Significant work has been done in recent years to understand pairwise relationships between the Goals. Now the scientific community should work to better understand the complexity of the SDGs, including the causal structures and feedback dynamics that give rise to SDG synergies and trade-offs and how these change over time.
• Assess policy impacts and implications. To increase the uptake of scientific assessments of global or non-place-specific patterns of SDG interlinkages, analyses should be more explicit about their relevance for decision making. This can be achieved in a few ways, such as by clearly stating assumptions about interventions, discussing policy implications of findings in more detail, and offering methods and data that can be used in institutionalized SDG impact assessments of new policy proposals by policymakers.

Our synthesis of the literature on SDG interlinkages can support decision making in the second half of SDG implementation. It can also inform what comes after. The 2030 Agenda emphasizes the importance of integration and indivisibility in addressing sustainability issues, encouraging a systemic approach. The formulation of the post-2030 Agenda should build on the efforts and lessons learned when operationalizing these principles in research and practice. Additionally, the 2030 Agenda has helped us understand the interrelationships between social, economic, and environmental sustainability and why certain Goals have seen limited progress. If researchers now start focusing more on the complexity dimension of the SDGs by identifying causal mechanisms that lead to both synergies and trade-offs, we can better comprehend the factors that drive or hinder progress. Leveraging this knowledge can allow the discussion on sustainable development post-2030 to be more focused and help set priorities for the future.