The Institute for Fiscal Studies (IFS) says there's a "conspiracy of silence" at this election; that all of the major political parties aren't being honest enough about their fiscal plans.   The thinktank says all the major parties are avoiding discussion around the black hole in their spending plans for after the election - but what else are they not talking about?    On the Sky News Daily, Niall Paterson is joined by economics and data editor Ed Conway to look at why topics from tax to Brexit might be missing from the campaigning.       Plus, Ed explains how exit polls, the first and most accurate early indications of who might win the general election on voting day, are put together.    Producer: Rosie Gillott  Editor: Paul Stanworth  Podcast promotions producer: Jada-Kai Meosa John