What do Suburban Rail Loop, Inland Rail, and East Coast High Speed Rail have in common? Yes, they’re all rail; yes, they’re all massive; but what’s really distinctive is that all three have business cases assessed with a lenient 4 per cent discount rate rather than the standard 7 per cent.

While it’s true that Australian governments generally don’t do a great job of setting discount rates, it’s also true that cherry-picking favourable rates for particular projects just makes the situation worse. What’s needed is a total overhaul.