Compare real alternatives before every major law: a Sen-inspired proposal for Spain

Every draft law in Spain travels with a document most citizens never read: the Memoria del Análisis de Impacto Normativo, the MAIN. It is meant to explain why the rule is needed, what it will cost, who it will affect and how it will be evaluated. Read alongside Amartya Sen's The Idea of Justice, it is also the obvious place to put his central idea to work. Justice advances, Sen argues, by comparing the feasible alternatives in front of us and choosing the one that does most for people's real freedoms. A law is one of those choices. The MAIN should show the comparison.

What the rules say today

Royal Decree 931/2017 sets out what the MAIN must contain. On alternatives it asks for two things. The report must justify the need for the rule against the alternative of approving no regulation at all. And, in the decree's own wording, as a general rule the ministry will try to assess more than one alternative ("se procurará valorar más de una alternativa"). The same decree requires a section on ex post evaluation: whether the rule is among those the annual regulatory plan will evaluate, its objectives, the deadlines and method for analysing results, and the body that will do it.

Law 27/2022 then built an evaluation system for central government. Ministries must ensure both an ex ante and an ex post evaluation of policies with significant budgetary impact or major expected social or economic effects. Evaluation is meant to be independent, objective and participatory, with its results, conclusions and recommendations made public. The law provides for a state evaluation agency that acts with independence and autonomy and reports to Parliament every year. After a final evaluation, the responsible body has two months to publish a results report setting out what it will do about each recommendation and justifying any it rejects.

At European level the Commission's Better Regulation Toolbox, in its version dated December 2025, gives officials dedicated tools for identifying policy options and for setting the baseline, the picture of what happens if nothing changes, alongside a Regulatory Scrutiny Board that reviews impact assessments.

So the pieces are there. The weak link is the word procurará, will try. A ministry can comply with the decree by comparing its preferred option with doing nothing, which is the easiest comparison to win.

The proposal

For every major law and regulation, meaning the policies with significant budgetary, social or economic impact that Law 27/2022 already singles out, the MAIN should contain a real comparison.

A baseline, honestly drawn: what happens over the next five or ten years with no new rule, including trends already under way.

The government's preferred option, with its costs, its effects on people's real opportunities and its effects on the households with least.

At least one serious rival option from a different policy tradition. If the government proposes public provision, the rival might be a regulated market or a voucher; if it proposes a tax incentive, the rival might be direct spending or a simple rule. The rival should be the best version of the alternative, the one its own supporters would put forward, and it should be assessed with the same data and the same methods.

The comparison should be published when the draft goes to consultation, so that those affected, including people outside the usual circle of stakeholders, can test it. That is Sen's open impartiality in practice: judgements that survive scrutiny from outside are the ones to trust. For the largest laws, the state evaluation agency or AIReF should review the comparison before the Council of Ministers approves the final text.

Then close the loop. The ex post evaluation the decree already requires should compare what happened with what the MAIN predicted for the chosen option, and say whether the rival would plausibly have done better. Under Law 27/2022 the government already has two months to respond to recommendations. That response should include whether to keep, change or replace the rule.

Why this is a radical-centre reform

From the left comes the democratic case: citizens have a right to see the options their government rejected and how each would have affected the people with least. A transparent comparison makes power explain itself. From the market-liberal tradition comes the discipline of the baseline: every new rule must show that it beats not regulating at all, which keeps red tape, compliance costs and hidden burdens in view. And from neither comes the idea at the centre of the proposal, borrowed from Sen: build comparison into the machinery of law-making itself, with a rival option from another tradition scored on equal terms and open to outside scrutiny.

The effect on politics could be larger than the effect on paperwork. A government that has to set out the strongest alternative to its own plan, and have it scored by the same rules, invites the opposition to argue about evidence. Sometimes the comparison will show that the rival is better, and the law will change before it is passed. Sometimes it will show that the government was right, and the law will pass with a stronger case. Either way, citizens see the choice that was actually made.

The cost is modest. Ministries already write the MAIN; the evaluation agency and AIReF already have the skills. What changes is one word in the decree, procurará becomes valorará, will try becomes will assess, and with it the habit of governing by comparison.