, ▁empir ical ▁evidence ▁cast s ▁doubt ▁on ▁the ▁link ▁proposed ▁by ▁Pet erson ▁& ▁Sel ig man ▁( 2 0 0 4 ) ▁between ▁the ▁ 2 4 ▁strength s ▁and ▁associated ▁ 6 ▁higher ▁order ▁virt ues . ▁ ▁Br dar ▁& ▁K ash dan ▁( 2 0 0 9 ) ▁used ▁more ▁precise ▁statistical ▁tools ▁to ▁build ▁upon ▁the ▁find ings ▁of ▁the ▁two ▁earlier ▁studies . ▁ ▁They ▁found ▁that ▁a ▁four ▁factor ▁model ▁( Inter person al ▁Str ength s , ▁V ital ity , ▁Fort itude ▁and ▁C aut ious ness ) ▁explained ▁ 6 0 % ▁of ▁the ▁variance . ▁ ▁One ▁large , ▁over arch ing ▁factor ▁explained ▁ 5 0 % ▁of ▁the ▁variance . ▁ ▁The ▁four ▁factors ▁found ▁by ▁Br dar ▁and ▁K ash dan ▁( 2 0 0 9 ) ▁are ▁similar ▁to ▁the ▁four ▁factors ▁found ▁by ▁Mac don ald ▁and ▁colle agues ▁( 2 0 0 8 ). ▁Once ▁again , ▁the ▁Br dar ▁and ▁K ash dan ▁found ▁that ▁the ▁ 2 4 ▁strength s ▁did ▁not ▁fall ▁into ▁the ▁ 6 ▁higher ▁order ▁virt ues ▁proposed ▁by ▁Pet erson ▁and ▁Sel ig man ▁( 2 0 0 4 ). ▁ ▁The ▁correl ations ▁found ▁between ▁many ▁of ▁the ▁strength s ▁demonstr ates ▁that ▁each ▁strength ▁is ▁not ▁distinct , ▁which ▁contradict s ▁the ▁claims ▁made ▁by ▁the ▁cre ators ▁of ▁the ▁VI A - IS . ▁ ▁Ca ution ▁should ▁be ▁taken ▁in ▁interpre ting ▁the ▁results