Recently, highly skilled workers in Eastern Europe have left jobs in record numbers to emigrate to the West.
Conclusion (therefore likely)
Skilled workers who remain in Eastern Europe are in high demand in their home countries.
Evidence
Highly skilled workers in Eastern Europe have left jobs in record numbers to emigrate to the West.
Evaluate
The argument posits that because many highly skilled workers are leaving Eastern Europe to move to the West, those skilled workers who stay behind must be in high demand. This suggests a scarcity of skilled workers leading to increased demand for those remaining. To weaken this argument, we would want to show evidence that undermines the claim that the remaining skilled workers are necessarily in high demand. We could show that the economic landscape no longer requires as many skilled workers, or that there are other factors preventing high demand for the remaining skilled workers.
Goal
To weaken this argument, we should find an answer that suggests either there is not a demand for skilled workers, despite their emigration, or that the skilled jobs are not as available or needed as the argument assumes.