Turnover intentions are the extent to which someone is planning to quit their current job. We have two turnover intentions scales. The first is 3-item that was used in Michaels and Spector (1982). The second is a 1-item version that was used first in Spector, Dwyer, and Jex (1988). In most studies I have used the single item just to save space, but 3-items would have greater reliability.
Michaels, C. E., & Spector, P. E. (1982). Causes of employee turnover: A test of the Mobley, Griffeth, Hand, and Meglino model. Journal of Applied Psychology, 67(1), 53-59. doi:http://dx.doi.org/10.1037/0021-9010.67.1.53
Spector, P. E., Dwyer, D. J., & Jex, S. M. (1988). Relation of job stressors to affective, health, and performance outcomes: A comparison of multiple data sources. Journal of Applied Psychology, 73(1), 11-19. doi:http://dx.doi.org/10.1037/0021-9010.73.1.11