  In this paper we take the reported measurements of black hole spin for black
hole X-ray binaries, and compare them against measurements of jet power and
speed across all accretion states in these systems. We find no evidence for any
correlation between the properties of the jets and the reported spin
measurements. These constraints are strongest in the hard X-ray state, which is
associated with a continuous powerful jet. We are led to conclude that one or
more of the following is correct: (i) the calculated jet power and speed
measurements are wrong, (ii) the reported spin measurements are wrong, (iii)
there is no strong dependence of the jet properties on black hole spin. In
addition to this lack of observational evidence for a relation between black
hole spin and jet properties in stellar mass black holes, we highlight the fact
that there appear to be at least three different ways in which the jet power
and/or radiative efficiency from a black hole X-ray binary may vary, two of
which are certainly independent of spin because they occur in the same source
on relatively short timescales, and the third which does not correlate with any
reported measurements of black hole spin. We briefly discuss how these findings
may impact upon interpretations of populations of active galactic nuclei in the
context of black hole spin and merger history.
