The introduction of a nationwide minimum wage in Germany has spurred a growth in worker productivity, according to a study published Tuesday. The government in Berlin first established a minimum wage in 2015, requiring firms to pay their employees €8.50 ($9.20) per hour. At the time, around 15% of the German workforce was earning less than that amount. Research by University College London (UCL) and the German Institute for Labor Market Research (AIB) found that the change did not result in higher joblessness among low-wage workers — one of the fears before the policy was rolled out. […] Instead, their...