But in the reality of the economic context we’re operating in, SI is one way of helping invest upfront to reap rewards further down the line – rewards of positive outcomes for people, as well as any financial returns.

Nick O’Donohoe recently referenced EIF’s work on late intervention costs in his thought-provoking piece in the Guardian. He noted the potential for SI and outcomes-based payment for services to help transform the lives of those who too often receive piecemeal support too late to make the impact that might have been delivered better for everyone earlier on.

The comments attracted by his piece, and the wider debate on SI, demonstrate that the financial returns element of SI remains controversial. Isn’t there always a risk that SI mechanisms become all about the money and doing whatever will deliver results to get the payment – even if that means prioritising the easiest cases, or focusing on short term wins for one outcome? O’Donohoe pointed out that this can be addressed by more nuanced sets of outcomes and looking at whether the positive results are sustained. Essentially, there’s a big difference between an outcomes-based payment mechanism – one that says, “if Mum gets into work, everything’s clearly hunky dory, and here’s a pile of money for your successful service” or “if we stop Daniel going into care it’s a good outcome” – and more sophisticated (and frankly more human) ways of measuring success that help reduce risk of ‘low-hanging fruit’ or ‘perverse incentives’.

In my view, it’s these additional, transparent measures around wider wellbeing, not necessarily associated with or possible to structure into repayment mechanisms, but vital for accountability and shining a light on the real social impact and success of a service or project, that are absolutely essential in SI structures.

If we know that Mum is in work, and is also less anxious and isolated, and making healthier lifestyle choices and sustains that over time; if we know that Daniel is not only still living safely at home but is getting into less trouble with his teachers and the police, and is feeling better about himself and self- managing his behaviour – well, then maybe that’s a service worth funding again, and one that can become sustainable in the long term too, delivering outcomes that reflect the complexity of lives. It is these measures that will demonstrate that it hasn’t been all about ‘low-hanging fruit’ and address scepticism about investors’ motivation.

Many SI mechanisms do take these into account. For example, the Essex SIB looks at outcomes around family relationships, wellbeing and engagement at school as well as whether the child is in care. But the case still stands to be better made around proving social investment really is ‘social’.

Dan Corry pointed out the big question mark remaining from the EngagedX report published recently looking at the financial returns from all the social investments to date – how are we to judge if the financial returns are worthwhile and if the projects are value for money or not without looking at the social outcomes too?

Each project and organisation funded by SI must be collecting social outcomes data. To really make the case for SI, to show that social impact is at least of equivalent importance as financial returns, and to make the most of the significant skills, capacity, and innovation of the agencies and individuals that SI uniquely draws together, social and financial outcomes must be considered together.

However, in the absence of any comprehensive overview of the social impact achieved by SI to date, there are signs that are cause for optimism. Just looking at SIBs, an area of particular interest to us in our work with local commissioners, the evidence is still limited as projects are still at early stage. However, where socially-motivated investors have been involved, it seems that – at least in the views of some involved – there can be a concerted focus on making the most of the flexibility of SIBs to ensure interventions work through challenges to deliver impact, in a way that might not have happened in less robust accountability structures, and an emphasis on outcomes measurement that really helps to improve rigour.

There are more SIBs coming along all the time, with varying structures that help address some challenges, like lengthy development times and huge scale requirements. Work in the UK has continued to make exciting progress, with SIBs that include the Fair Chance Fund projects supporting young homeless people into education, employment, and accommodation; help for young people not in education, employment or training through theYouth Engagement Fund, including two ‘follow-on’ SIBs with Teens and Toddlers and Careers Connect that have already demonstrated success under DWP Innovation Fund SIBs. A pioneering new foster placement scheme funded by a SIB is in place in Birmingham, work around reducing social isolation and loneliness in older people in Worcestershire, and really promising developments in Newcastle, with the first ever CCG-commissioned SIB around long-term conditions and social prescribing – amongst others!

Further afield, in the US, while the policy context and market is different, we watch with interest while the further SIBs around early years education develop, including the world’s biggest investment in a SIB in Chicago’s pre-school child-parent centres, with repayment based on measures including school readiness, and work to launch SIBs is pursued in multiple states around areas such as child and maternal health and teenage pregnancy. The mechanisms, measures, and impact of these projects could hold ideas for similar projects here. In Lisbon, a SIB is funding school projects teaching children to code – demonstrating the possibility of using SIB approaches to fund results on a small scale, that don’t need immediate savings associated with them.

So what’s next here? The new government’s manifesto has committed to supporting SIBs in areas of real interest to EIF. As lessons and results begin to emerge from the Essex SIB, the opportunities are ripe and there for the picking. Personally, I’m excited about whether SIBs could be used to tackle areas of really challenging and costly service use patterns – like mums (and their partners) who’ve had children removed before and are pregnant again with a risk of that baby being taken into care; children and young people experiencing mental health problems; even perhaps the very challenging area of domestic violence and abuse. There’s more to do to support more edge of care interventions, and potentially early years support – and EIF’s growing evidence base can help to build confidence among commissioners and investors alike about the potential for early intervention to deliver on the ‘double bottom line’.

To achieve this, more of us still need to work hand in hand with local commissioners to build the capacity to monitor and hold services to account by outcomes. Working at EIF is a journey of being simultaneously amazed at the innovation, creativity, and sheer determination, professionalism and skill with which local services are helping children and families, while also often being alarmed by the lack of systems to measure impact with rigour. Securing investment in early intervention and SIBs alike will face an uphill battle as long as impact measurement, outcomes-focussed commissioning, and cost-benefit considerations remain the preserve of geeky sorts who like spreadsheets and those who used to work for banks. It needs to register among the priorities and opportunities for those who are busy juggling panel decisions about vulnerable children’s lives, forthcoming inspections, service restructures, appeals, and supervising stressed staff too. Commissioners who are already on board could be much better supported to be champions. The question needs asking to anyone who now has an interest in this area who didn’t a year ago – why? And to prove to commissioners it can work, did somebody else do it who is like us? How?