Suppose the graph to the right shows the market for people who assemble Video Cassette Recorders (VCRs). Demand for these workers could shift out due to any of the following:

Increase in income if VCRs are normal goods.
Increase in the price of Digitial Video Disc Players (DVDs), a substitute.
Decrease in the price of pre-recorded movies and blank tapes, both complements..
Expectations of rising prices for VCRs in the near future.
Change in tastes making taping TV shows and watching rented movies more popular.