They’d managed to attract some of the biggest players in the field, and to explore challenges and opportunities in depth and at a level of honesty I’ve rarely seen at previous events on social investment. It was also an energising and inspiring day for those of us excited by the possibilities of the world-leading innovation that the Essex social impact bond (SIB) for MST represents.

SIBs have had varying press over the years and there’s been a lot of speculation in the past couple of months following the demise of the Peterborough SIB, which for some was the sign they had been waiting for heralding the end of the dream, the ‘death of SIBs’. I think this conclusion is a bit extreme – certainly the changes have demonstrated that SIBs (like any model) are vulnerable to changes in policy and approaches over time, but actually, one of the strengths of the SIB structures may be enabling the establishment of services that can change over time and mechanisms that evolve to meet the needs of new requirements of policy, and perhaps more importantly, a focus on outcomes rather than a fixed and unchangeable method and activities.

In Essex, one of the messages that came over loud and clear to me was the benefits of the SIB model in creating flexibility to learn and adapt, as needs become more obvious, processes are honed, and lessons learned. The scope to test and develop evolving solutions that learn from trial and error about what is best at delivering outcomes, as a project or programme is delivered, rather than having to wait til the next commissioning round or strategy refresh, seems like a real benefit for innovation and learning.

But what struck me most strongly from Essex is how the process of establishing social investment mechanisms – or even simply considering their feasibility – is leading to some fantastic developments and learning that are of real interest for early intervention more broadly.

Firstly, making a good business case for social investment hinges on robust understanding of needs of the population being targeted, analysis of current costs associated with those populations’ needs, and potential savings from avoiding these, clear understanding of outcomes sought, ways to ensure robust measurement of these (including understanding how this compares to what would have happened anyway without any intervention), and a good understanding of what kind of interventions might actually work to deliver the desire outcomes.

The experience of places that have gone through the process of thinking about or setting up SIBs shines a light on some of the challenges associated with these issues – not least the limitations of data available, difficulties in accessing it, and a real need to build better understanding, capacity, and systems to be able to understand and analyse outputs and outcomes, to know how to demonstrate counterfactuals, and put in place mechanisms to see how well things are working.

Secondly, delivering an evidence-based programme funded through a SIB requires a process of implementation within an existing local system that offers much to learn from for anyone implementing new services, programmes or teams. Lessons around ensuring that referral systems are set up to channel the right referrals and that everyone in other services understands the role of the team, making sure practitioners are working coherently with other services, sharing data efficiently, and ensuring that a steady team is maintained, are relevant to anyone delivering EI.

Many of these challenges are things that EIF is working on supporting improvement in in our EI Places and beyond, not least through our newly-launched Guidebook, and it is good to see that the drive to find out if social investment is a plausible way to fund EI and other services seems to be encouraging work on these vital issues.

However, there’s probably too little emphasis at the moment on the extent to which SIB mechanisms really help enable implementation of EI services in a more effective or efficient way than any other sort of commissioning approach. We know many of the pros and cons of using SIBs in general, but what can be said about the value for money of the SIB model itself? Could a place weigh up the costs and benefits of going down this route, compared to any other?

Those embarking on the SIB journey are taking a certain leap of faith at the moment – which is great for innovation and much needed to help understand what the potential is for these mechanisms. In some cases, like Essex, there’s exciting progress to consider. But over time, it will be important for us all to understand better not just how well things are working in the services funded by SIBs, and the lessons learned from implementation, but what innovative financing mechanisms themselves have to offer to areas’ EI journeys and beyond.