Policy pilots in Spain: why radical centrism says experiment first, with the minimum income lab as proof

Rule 9 of the radical centre constitution we finished today says: test before rolling out nationwide. Try a reform on a small scale, measure what happens, then generalise what works. It sounds like common sense, and in Spain it already has a strong precedent. Between 2021 and 2024 the Ministry of Inclusion ran an unusually ambitious set of policy experiments. The case for making that the normal way to legislate is now easy to make.

What Spain already did

When the minimum income scheme, the Ingreso Mínimo Vital, was approved in 2020, the ministry also set out to learn what helps its recipients find work and leave poverty. With money from the EU recovery plan, it funded 34 pilot projects of social and labour inclusion, run with regional governments, city councils and charities. Two could not go ahead. The remaining 32 were evaluated as randomised controlled trials, the same method used in clinical trials: participants are assigned by lottery to receive the programme or to a control group, so the difference between the groups can be put down to the programme.

The scientific partners were CEMFI, the Madrid economics research centre, and J-PAL, the network founded at MIT by the Nobel laureates Esther Duflo and Abhijit Banerjee. J-PAL describes the set-up: the ministry funded interventions proposed by NGOs and regional and local governments, on condition that they agreed to a randomised evaluation, with around eighteen university researchers coordinated by CEMFI. The ministry's final report, published in May 2024, says no public administration had previously run 32 randomised trials in a coordinated way.

The scale was serious. About 91,000 people took part in the trials, counting treatment and control groups, and more than 175,000 benefited once their households are included. The results vary from project to project, which is exactly what a policymaker needs to know. Personalised job guidance in Navarra increased days worked by 13.7%. In Castilla-La Mancha it raised the probability of being employed by 28%. In Extremadura, participants increased their hours worked by 67%. One of the report's ten recommendations is blunt: giving people information is not enough, and closing the gap in benefit take-up requires face-to-face support that builds trust. Its last recommendation is to reinvest what was learned in scaling up the best practices.

Two more pilots worth knowing

Barcelona had already shown the method at city level. Its B-MINCOME project, which ran from November 2016 to October 2019 with €4.85 million from the European Regional Development Fund, combined a guaranteed minimum income with active policies such as training, the social economy and community participation, in ten of the city's poorest neighbourhoods. Of 2,525 households that applied, 1,527 were found eligible. Demand exceeded the money available, so places were allocated by lottery, about 1,000 households to treatment and over 400 to control. The lottery solved two problems at once. It was the fairest way to share scarce places, and it made a clean evaluation possible.

Finland went national. Its social insurance institution, Kela, paid 2,000 unemployed people a tax-free basic income of €560 a month for two years, with participants chosen at random and taking part compulsorily. The results, published in 2020, showed small effects on employment and clear improvements in wellbeing: more life satisfaction, less psychological distress, less bureaucracy and more confidence in the future. Kela's own conclusion is that the experiment proved a nationwide randomised field trial can be planned, carried out and evaluated. A big, contested idea was tested at modest cost, and the debate afterwards could rest on data.

Making experiments the default

Spain now has the institutions to do this routinely. Ley 27/2022 requires ministries to evaluate policies with significant budgetary or social impact, before and after, and authorised a State Agency for the Evaluation of Public Policies. The agency's statute was approved by Royal Decree 65/2026 in February. It is attached to the Ministry of Economy, succeeds the former evaluation institute, and its functions include developing evaluation methods, managing a common system of indicators and training public employees.

The law speaks of evaluation; it says little about experiments. That is the gap a radical-centre reform would close. The proposal is simple. Any new programme above a set budget, or any major redesign of an existing one, starts as a pilot in a limited number of regions or cities, with a randomised or comparable design agreed with the agency in advance. The evaluation is published, whatever it shows. Only then does the government ask parliament to legislate for the whole country. Where a programme is oversubscribed, as B-MINCOME was, places are allocated by lottery, openly.

This combines ideas that rarely sit together. From the left: the minimum income and the personal support that came with these pilots are public duties, and the 2024 results show they can be made to work better. From the right and the market tradition: public money has to prove its value, and programmes that do not deliver should be redesigned or dropped. And from neither camp comes the experiment itself, a democratic tool that turns arguments about ideology into questions evidence can answer. It is Amartya Sen's comparative method made practical, comparing real alternatives on real people, and it is Mark Satin's instruction to borrow from any tradition and judge by results, given an institution to carry it out.

Spain did the hard part between 2021 and 2024: it showed its administration could run dozens of randomised trials at once. The next step is to make that the rule.