This is the fifth and final summary paper of our 15 year program using the Hubble Space Telescope ( HST ) to determine the Hubble constant using Type Ia supernovae , calibrated with Cepheid variables in nearby galaxies that hosted them .
Several developments not contemplated at the start of the program in 1990 have made it necessary to put the summary on H _ { 0 } on a broader basis than originally thought , making four preparatory papers ( cited in the text ) necessary .
The new Cepheid distances of the subset of 10 galaxies , which were hosts of normal SNe Ia , give weighted mean luminosities in B , V , and I at maximum light of -19.49 , -19.46 , and -19.22 , respectively .
These calibrate the adopted SNe Ia Hubble diagram from Paper III to give H _ { 0 } = 62.3 \pm 1.3 ( random ) \pm 5.0 ( systematic ) in units of { km s } ^ { -1 } Mpc ^ { -1 } .
This is a global value because it uses the Hubble diagram between redshift limits of 3000 and 20 000 { km s } ^ { -1 } reduced to the CMB kinematic frame , well beyond the effects of any local random and streaming motions .
Local values of H _ { 0 } between 4.4 and 30 Mpc from Cepheids , SNe Ia , 21 cm-line widths , and the tip of the red-giant branch ( TRGB ) all agree within 5 % of our global value .
This agreement of H _ { 0 } on all scales from \sim 4 - 200 Mpc finds its most obvious explanation in the smoothing effect of vacuum energy on the otherwise lumpy gravitational field due to the non-uniform distribution of the local galaxies .
The physical methods of time delay of gravitational lenses and the Sunyaev-Zeldovich effect are consistent ( but with large errors ) with our global value .
The present result is also not in contradiction with existing analyses of CMB data , because they either lead to wide error margins of H _ { 0 } or depend on the choice of unwarrented priors that couple the value of H _ { 0 } with a number of otherwise free parameters in the CMB acoustic waves .
Our value of H _ { 0 } is 14 % smaller than the value of H _ { 0 } found by Freedman et al .
( 53 ) because our independent Cepheid distances to the six SNe Ia-calibrating galaxies used in that analysis average 0.35 \mbox { $ $mag } larger than those used earlier .