Here they use information gathered form Cepheids, are these parallax measurements accurate? From science daily. Date: June 2, 2016 Source: Space Telescope Science Institute (STScI) Summary: Hubble Space Telescope astronomers have discovered that the universe is expanding 5-9% percent faster than expected. They made the discovery by refining the universe's current expansion rate to unprecedented accuracy, reducing the uncertainty to only 2.4%. The team made the refinements by developing innovative techniques that improved the precision of distance measurements to faraway galaxies. These measurements are fundamental to making more precise calculations of how fast the universe expands with time, a value called the Hubble constant.