Here's a very readable paper about the various efforts past, present, and future that are producing large scale systematic observations of millions of stars cataloging and categorizing the different types of variables, down to a variability of a few thousandths of a magnitude. The bulk of the article is about the Gaia mission, but it also covers Hipparchos, OGLE I & II, Pan-STARR, LSST, and others. Some of these surveys go down to 24th magnitude, and will enable rock solid statistical analysis in many new fields.
VARIABILITY ANALYSIS: DETECTION AND CLASSIFICATION

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Didn't Hipparcos produce distance measurements that were about ten percent off?

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...and we'll be saying a big hello to all intelligent life forms everywhere; and to everyone else out there, the secret is to bang the rocks together, guys...

Hipparchos measured parallax, but picked up star variability at the same time.
The amount that the Hipparchos measurements were off depended on how far the star was. It was about 10% off to the Pleides, but much less than 1% to Alpha Centauri.

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That's the one! I knew I had heard an example of Hipparcos being off by 10%. The Pleides was the one. How could a paralax measurement be that far off for one of the closest stars there is (alpha Centauri)? You'd figure they could get that one right...

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...and we'll be saying a big hello to all intelligent life forms everywhere; and to everyone else out there, the secret is to bang the rocks together, guys...

It might have been the Hyades that was off by 10%, I'd have to look it up. In any case, we haven't exactly been out with a tape measure to validate the distances. The probe simply had a very precise method of determining parallax, down to about 3 milli-arcseconds.

Stars that were more than 50 parsecs away didn't get much precision.

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