▁within ▁the ▁domain ▁of ▁social ▁behavior ▁could ▁be ▁identified . ▁ ▁Thus , ▁factor ▁analysis ▁could ▁be ▁used ▁to ▁discover ▁the ▁fundamental ▁dimensions ▁underlying ▁the ▁large ▁number ▁of ▁surface ▁behav iors , ▁thereby ▁facil it ating ▁more ▁effective ▁research . ▁ ▁As ▁noted ▁above , ▁C att ell ▁made ▁many ▁important ▁innov ative ▁contributions ▁to ▁factor ▁analyt ic ▁method ology , ▁including ▁the ▁Sc ree ▁Test ▁to ▁estimate ▁the ▁optimal ▁number ▁of ▁factors ▁to ▁extract , ▁the ▁" Pro cr ust es " ▁ob lique ▁rotation ▁strategy , ▁the ▁Co efficient ▁of ▁Profile ▁Similar ity , ▁P - te chni que ▁factor ▁analysis , ▁d R - te chni que ▁factor ▁analysis , ▁the ▁Tax on ome ▁program , ▁as ▁well ▁the ▁Rot op lot ▁program ▁for ▁att aining ▁maximum ▁simple ▁structure ▁solutions . ▁In ▁addition , ▁many ▁em inent ▁research ers ▁received ▁their ▁ground ing ▁in ▁factor ▁analyt ic ▁method ology ▁under ▁the ▁guidance ▁of ▁C att ell , ▁including ▁Richard ▁G ors uch , ▁an ▁authority ▁on ▁expl or atory ▁factor ▁analyt ic ▁methods . ▁ ▁Person ality ▁theory ▁In ▁order ▁to ▁apply ▁factor ▁analysis ▁to ▁person ality , ▁C att ell ▁believed ▁it ▁was ▁necessary ▁to ▁sample ▁the ▁wid est ▁possible ▁range ▁of ▁variables . ▁ ▁He ▁specified ▁three ▁kinds ▁of ▁data ▁for ▁compreh ensive ▁sampling , ▁to ▁capture ▁the ▁full ▁range ▁of ▁person ality ▁dimensions : ▁ ▁Life ▁data ▁( or ▁L - data ), ▁which ▁involves ▁collect ing ▁data ▁from ▁the ▁individual ' s ▁natural , ▁every day