As a centrist I think the left-right political spectrum does as much mischief as good, because it encourages a false polarization of what we think the political options are. Nonetheless, it is very useful. Most people can readily place themselves on the spectrum, and choose their friends and enemies based on whether those others call themselves left or right.
James Rockey, an economist at the University of Leicester, has an interesting analysis based on the World Values Survey called "Who is left, and who just thinks they are?" He compared where people places themselves on a ten-point left/right spectrum with where they place themselves on two other questions to get some objective measure of their actual position. One of the objective questions is familiar:
“Incomes should be made more equal vs We need larger income differences as incentives. How would you place your views on this scale?"
The second question sounds unusual, at least to American ears:
"Imagine two secretaries, of the same age, doing practically the same job. One finds out that the other earns considerably more than she does. The better paid secretary, however, is quicker, more efficient and more reliable at her job. In your opinion, is it fair or not fair that one secretary is paid more than the other?"
Rockey's headline finding: the more educated on average believe themselves to be more left wing than their actual beliefs on a substantive issue might suggest.