Diminishing marginal returns - By investing in hiring an additional worker, Michelle does not receive twice the productivity compared to when she had only 1 worker. Productivity only increased by roughly 50%. I would consider the worker to be more of an investment, and thus count as diminishing marginal returns, rather than decreasing returns to scale, which I consider to apply more to assets, such as machines for manufacturing or in the case of the scenario, an additional kiln.
