I remember in getting my MBA, the Management professor talked about Albert Speer discussing using slave labor in munitions plants during the war. The SS decided that women laborers with smaller hands were ideal for assembling fuses for bombs. And if the highly dangerous item exploded during manufacture, it would be a worthless slave who was injured or killed.
However, productively from the fuse plants was terrible and got worse, so Speer, in overall command of wartime production, though not SS, went to examine the plant. It turned out that it was very easy for a worker to sabotage the fuse during assembly so that it was a dud. The SS's first brilliant idea was to test first every other fuse. However, this meant production after testing was cut by 50%. So instead they tried increasing the number of guards watching the assembly. This had no effect at first because the guards stood so far away for safety that even with increased numbers they saw nothing. So the guards were ordered to get right by the worker to watch. This, however, meant that injuries among guards increased. And it still didn't make a major impact on the # of duds. The workers, of course only sabotaged when a guard was elsewhere. So the number of guards was increased. When Speer arrived at the plant, he found there was one SS guard for each worker, standing right by the worker with his face close to the fuse. The number of duds was reduced by 80%. But the cost of the plant was now a full complement of full cost personnel (the guards) and a full complement of low cost personnel (the slaves). And the slaves even under close supervision only worked on average at 75% efficiency and 20% were duds (and a dud fuse meant a dud bomb, costing much more than the fuse).
The Management professor drew two lessons of the class from this. One, under-motivated or dissatisfied workers are particularly bad in high-tech work. Two, the SS management was so blinded by its ideas of power and control that they were amazingly stupid in the implementation. (German efficiency is not always reamarkable)