It is easy for people working at respectable institutions to get a little comfortable, to assume that the logo on their work will mean it gets a hearing despite serious weaknesses.

They know that we all have a limited attention span when it comes to politics and get used to the idea that, by the time the assumptions underlying it all become apparent, the right headlines have already been published.

The OECD report on the economic impacts of Brexit seems like a prime example. The assumptions about what will happen after a deal are a little crazy.