Speaking of immigration, immigration is not absolutely productive. There are a myriad of factors at play here. If one wishes to inject a population with a group in order to increase the population’s overall productivity, they must ensure that the injected group is as-productive or more productive than the original population.
I don’t think whether the group’s average output increases or decreases is the right metric. What’s important is whether the newly enlarged group’s output is higher than what the group and its new members’ total output would be if the groups weren’t merged—do the immigrants become more productive by immigrating, and do they make the native population more or less productive?
Speaking of immigration, immigration is not absolutely productive. There are a myriad of factors at play here. If one wishes to inject a population with a group in order to increase the population’s overall productivity, they must ensure that the injected group is as-productive or more productive than the original population.
I don’t think whether the group’s average output increases or decreases is the right metric. What’s important is whether the newly enlarged group’s output is higher than what the group and its new members’ total output would be if the groups weren’t merged—do the immigrants become more productive by immigrating, and do they make the native population more or less productive?