The bed sofa I ordered from John Lewis is arriving tomorrow morning between 7.19 and nine o’clock according to the text they sent. You wonder why institutions (John Lewis. governments) insist on the fiction of precision in their estimates. Given London traffic, given the vagaries of time and place; given the five pints that the van driver may have had the night before; given any number of changes to plans or weather or accidents or demontrations or road works, it is highly unlikely that the van will pitch up at 7.19 precisely. If it arrives at 7.18, will the driver wait a minute before knocking on my front door? Why not say 7.15 or 7.20 and have done with it? Why not accept that this is a rough estimate? Embrace the rough estimate. Who is fooled when you claim to control all variables? Do they think we believe that 7.19 is an accurate time? Of course, government estimates for the prices of public projects are equally pin-prick precise and equally way off the mark of the actual cost. The cost of transforming the Olympic Stadium in London into a football ground for West Ham United was £190 million but actually cost £320 million. The Jubilee line was estimated at £2.1 billion and came in at £3.5 billion. This is habitual blackmail. Once a big project contract has been won, you can’t turn back and leave yourself vulnerable to any hiking of prices, legitimate or otherwise. None of this explains the 7.19 estimate. Probably spewed out by a computer. What the John Lewis executives who manage this type of information fail to understand is that the customer can understand that an arrival time is a rough science and the pretence that all variables can be controlled is a silly boast. Why let the computer make you look silly like that.