We report the combination of recent measurements of the helicity of the
W boson from top quark decay by the CDF and D0 collaborations, based on
data samples corresponding to integrated luminosities of 2.7-5.4 fb(-1)
of p (p) over bar collisions collected during Run II of the Fermilab
Tevatron collider. Combining measurements that simultaneously determine
the fractions of W bosons with longitudinal (f(0)) and right-handed
(f(+)) helicities, we find f(0) = 0.722 +/- 0.081[+/- 0.062(stat) +/-
0.052(syst)] and f(+) = -0.033 +/- 0.046[+/- 0.034(stat) +/-
0.031(syst)]. Combining measurements where one of the helicity fractions
is fixed to the value expected in the standard model, we find f(0) =
0.682 +/- 0.057[+/- 0.035(stat) +/- 0.046(syst)] for fixed f(+) and
f(+) = -0.015 +/- 0.035[+/- 0.018(stat) +/- 0.030(syst)] for fixed
f(0). The results are consistent with standard model expectations