We’ve all had those days when we were much younger, when our boss asked us to produce a five/ten/twenty year forecast of whatever was taking his fancy at the time. The forecast would take into account economic cycles, inflationary expectations, disposable incomes, family sizes and so on. To make it credible all assumptions should be detailed and justified.
I suspect that something like that happened recently in Babergh & Mid Suffolk’s housing department when someone was asked to produce a twenty-year plan for housebuilding based on whatever factors were deemed relevant.
The answer is 17,568 homes over twenty years.
Note the precision.
Who believes this rubbish? In the real world our boss would have either called it 17,500 or being a clever sort, he might have said 15,000 so he could under promise and over deliver. If he was on the brink of an unwelcome retirement, he would have rounded the figure up to 25,000 so that his successors would be forever on the wrong end of target fulfillment.  
But he would have realized early on that the further away you are from the present the less reliable is your forecast and the more precise it is, the more it will attract criticism & derision.

Unfortunately, many of our public servants do not review their public utterances – hence precision taking precedence over accuracy and unreliable statistics rule our lives.