cess ion . ▁Mark ▁Thor nt on ' s ▁Sk ys cra per ▁Index ▁Model ▁successfully ▁sent ▁a ▁signal ▁of ▁the ▁late - 2 0 0 0 s ▁financial ▁crisis ▁at ▁the ▁beginning ▁of ▁August ▁ 2 0 0 7 . ▁ ▁The ▁buildings ▁may ▁actually ▁be ▁completed ▁after ▁the ▁on set ▁of ▁the ▁re cess ion ▁or ▁later , ▁when ▁another ▁business ▁cycle ▁pull s ▁the ▁economy ▁up , ▁or ▁even ▁cancel led . ▁Un like ▁earlier ▁instances ▁of ▁similar ▁reasoning ▁(" height ▁is ▁a ▁bar ometer ▁of ▁bo om "), ▁Lawrence ▁used ▁sk ys cra per ▁projects ▁as ▁a ▁predict or ▁of ▁economic ▁crisis , ▁not ▁bo om . ▁ ▁One ▁statistical ▁study ▁found ▁that ▁the ▁height ▁of ▁buildings ▁is ▁not ▁an ▁accurate ▁predict or ▁of ▁re cess ions ▁or ▁other ▁aspects ▁of ▁the ▁business ▁cycle , ▁but ▁that ▁G DP ▁can ▁predict ▁the ▁height ▁of ▁building ▁construction . ▁ ▁Details ▁Lawrence ▁started ▁his ▁paper , ▁The ▁Sk ys cra per ▁Index : ▁F ault y ▁Tow ers , ▁as ▁a ▁jo ke ▁( emph as ized ▁by ▁a ▁title ▁referencing ▁a ▁comedy ▁show ) ▁and ▁based ▁his ▁index ▁on ▁a ▁comparison ▁of ▁historical ▁data , ▁primarily ▁from ▁the ▁United ▁States ' ▁experience . ▁He ▁dismiss ed ▁overall ▁construction ▁and ▁invest ment ▁statistics , ▁foc using ▁only ▁on ▁record - bre aking ▁projects . ▁The ▁first ▁notable ▁example ▁was ▁the ▁Pan ic ▁of ▁ 1 9 0 7 . ▁Two ▁record - bre aking ▁sk ys c rap ers , ▁the