What was the effect of unemployment after WWI?
I assume you are referring to the effects in Germany, as the U.S. was in growth mode until the crash of 1929. Germany, however, was punished so severely after World War I that unemployment was rampant and the money worth almost nothing. People were starving because even if any food or goods were available, they were beyond the reach of most people, especially considering that to buy a loaf of bread cost a wheelbarrow full of money. What this did was set the scene for Hitler to rise to power, blame the Jews for all the trouble Germany was in economically, and appeal to Germany's sense of military entitlement. The treaty that ended World War I was a disaster because Germany's punishment was the wrong way to proceed once the war was over, as unemployment fed Germany's anger about how they were treated with people starving everywhere.