Throwing big numbers around ignores the economic questions that really matter | Carys Roberts

The Tories' obsession with policy costings as the only measure of economic credibility is austerity logic in action

This week the election campaign has been squarely focused on public finances, with the Conservatives publishing a widely derided 1.2tn assessment of Labour's spending plans. In spite of the debunking of these figures, the party has doubled down with a separate assessment of Labour's tax plans - it says Labour's spending plans outweigh how much it plans to collect in tax, leading to a 2,400 per taxpayer "gap" that will need to be filled by borrowing or raising taxes.

Of course, the Conservatives are aware of the quality of the claims they are making. As a tactic, the 1.2tn is straight out of the "350m a week" playbook: come up with a big figure, and no matter if it's indefensible, wait for it to stick. The more your opponents complain, the more they end up repeating the big number until it's indelibly imprinted on voters' minds.

While we're all obsessing over the numbers, we lose sight of the questions that really matter

Related: Worsening public finances give next PM a sharp 'reality check'