Original sentence: The study yielded two well-defined eigenvectors (i.While multiple axes on the political spectrum had been postulated for a while, statistical analysis of survey data using principal component analysis was not done until recently.groups of questions that tend to be answered consistently), indicating that the political spectrum may be most sensibly described with two axes
Edited sentence: In a recent study, statistical analysis of survey data with principal component analysis yielded two well-defined eigenvectors (i.While multiple axes on the political spectrum had been postulated for a while their existence had never been proved conclusively until recently.groups of questions that tend to be answered consistently), indicating that the political spectrum is indeed most sensibly described with two axes