This paper has stated the theoretical framework of Okun’s law (LO) and an integrated IS-LM-LO model to better understand the effects of economic policies on unemployment. Stated and demonstrated, the Okun law theorem confirms the existence of a negative link between economic growth and variation in the unemployment rate. However, this Okun relation cannot be considered stable. Among other things, demographic shocks, shocks onto the average real wage, real gross profits, importation duties and net taxes on goods and services induce structural changes in Okun’s relation. The structural change in Okun’s relation can be virtuous or vicious. When economic dynamic generates a vicious structural change in Okun’s relation so that the Okun new threshold it induces is always higher than the observed economic growth rate, the unemployment rate increases. Economic growth has a greater impact on unemployment when it is strong and engenders a virtuous structural change in Okun’s relation. Thus, analysis of the IS-LM-LO model shows that, though fiscal or monetary policy have a positive effect on economic growth, it would lead to an increasing unemployment if it engenders a vicious structural change in Okun’s relation. The most effective economic recovery policy to take on unemployment is the one that, in addition to accelerating economic growth, induces a virtuous structural change in Okun’s relation.