Randy Black said:An unemployment rate of 4% or slightly less is de facto full employment, on the theory that there will always to be about 3-4% of the workforce unemployed, no matter how great the economy. Cameron Sawyer comments: Well, obviously. An office building which is 95% full, for example, is considered completely full. That is because of the normal moving in and out of tenants. Thus with the employment market. A certain number of employees change jobs every few years. This amounts to 4% or so unemployment -- people literally "between jobs".