 Shirking models were particularly influential.Carl Shapiro and Joseph Stiglitz's 1984 paper "Equilibrium Unemployment as a Worker Discipline Device" created a model where employees tend to avoid work unless firms can monitor worker effort and threaten slacking employees with unemployment.If the economy is at full employment, a fired shirker simply moves to a new job.Individual firms pay their workers a premium over the market rate to ensure their workers would rather work and keep their current job instead of shirking and risk having to move to a new job.