Kepler has really been a game-changer for our understanding of the incredible diversity of planets and planetary systems in our galaxy," said Douglas Hudgins, a scientist with NASA's astrophysics division.
The new technique is called "verification by multiplicity," and relies in part on the logic of probability. Instead of searching blindly, the team focused on stars that the technique suggests are likely to have more than one planet in their orbit.
NASA says 95% of the planets discovered by Kepler are smaller than Neptune, which is four times as big as Earth.
One of them is about twice the size of Earth and orbits a star half the size of Earth's sun in a 30-day cycle.
The other three planets in habitable zones also are all roughly twice the size of Earth. Scientists said the multiplicity technique is biased toward first discovering planets close to their star and that, when further data comes in, they expect to find a higher percentage of new planets that could potentially have a life-supporting climate like Earth's.
"The more we explore the more we find familiar traces of ourselves amongst the stars that remind us of home," said Jason Rowe, a research scientist at the SETI Institute in Mountain View, California, and co-leader of the research team.