Top cities to travel to in the us for Spence pointed out that these workers may have another option. Instead of working at the average wage, they may attempt to signal their higher ability to the employer and demand a higher wage. In order for a signal to yield a higher wage offer, it must be the case that the signal reveals the worker’s ability. The high-productivity worker has to find a credible signal that low-ability workers would find too costly, even if they were subsequently granted a very high wage. In Spence’s (deliberately highly stylized) model, education serves as such a signal. It is assumed that education is costly due to the effort spent on obtaining a degree. People who tend to be more productive, however, find it less costly to do so than people who are less productive. Top cities to travel to in the us 2016.