The mobility of labour refers to the ease with which workers can move from one job or location to another in search of better opportunities. This mobility is mainly determined by wage rate differentials, which are the differences in pay between different jobs or regions. If the wage rate is higher in a particular location or occupation, workers are more likely to move there, increasing the mobility of labour. On the other hand, if the wage rate is lower or stagnant, workers may be less inclined to move, reducing the mobility of labour. While government policies and trade unions may also affect labour mobility to some extent, wage rate differentials are the primary driver.