Having a look on Wikipedia I noticed the following values (of the last 6 years) for the Hubble constant:
- 67.6±0.7 SDSS-III Baryon Oscillation Spectroscopic Survey
- 73.00±1.75 Hubble Space Telescope
- 67.80±0.77 Planck Mission
- 69.32±0.80 WMAP (9-years)
- 70.4±1.3 WMAP (7-years)
Most of experiments exclude the values of the others so that WMAP excludes the values of SDSS and from Hubble, while Hubble excludes Plank Mission's values, SDSS and WMAP 9. Can anybody tell what's the problem here and which one is the more reliable source for $H_0$?