A common concern is that by adding to the supply of labour, immigration can reduce the wages of local workers (or displace them from jobs). This concept of displacement is partly a manifestation of a fallacy that there is a fixed number of jobs in an economy. However, with sufficient labour market flexibility, displaced workers will typically seek and find other new jobs, although potentially at lower wages than their previous employment. Offsetting this effect is the increase in demand for local goods and services from new immigrants. Immigrants also may complement rather than displace local workers, improving productivity, particularly when filling skill shortages that are restricting the expansion of firms.