SWEDES discuss their incomes with a frankness that would horrify Britons or Americans. They have little reason to be coy; in Sweden you can learn a stranger’s salary simply by ringing the tax authorities and asking. Pay transparency can be a potent weapon against persistent inequities. When hackers published e-mails from executives at Sony Pictures, a film studio, the world learned that some of Hollywood’s most bankable female stars earned less than their male co-stars. The revelation has since helped women in the industry drive harder bargains. Yet outside Nordic countries transparency faces fierce resistance. Donald Trump recently cancelled a rule set by Barack Obama requiring large firms to provide more pay data to anti-discrimination regulators. Even those less temperamentally averse to sunlight than Mr Trump balk at what can seem an intrusion into a private matter. That is a shame. Despite the discomfort that transparency can cause, it would be better to publish more information….