Here are the elements that Frank and co-author Woodruff Sullivan (of the astronomy department and astrobiology program at the University of Washington) propose could be changed:

• How many stars have habitable planets? 1/5 of stars have planets in habitable zones. This is known due to the Kepler space telescope’s search of exoplanets as well as other planetary research.
• How long can civilizations survive? That question is very hard to answer, so the researchers instead asked “Are we the only technological species that has ever arisen?” More on that subject later in this article.
• How likely is it for advanced life to arise on a planet? The researchers instead tried to imagine a universe where humanity is the only one. By applying this probability question to the number of known stars the researchers found a probability of one in 10 billion trillion. In our own Milky Way, the number rises to just one chance in 60 billion.