For a realistic interpretation of it legitimately allows for various inexactnesses of adjustment which stand in the way of continuous full employment: for example, unemployment due to a temporary want of balance between the relative quantities of specialised resources as a result of miscalculation or intermittent demand; or to time lags consequent on unforeseen changes; or to the fact that the change over from one employment to another cannot be effected without a certain delay, so that there will always exist in a non static society a proportion of resources unemployed 'between jobs'.