▁In ▁bo om ▁times , ▁rational ▁pr icing ▁gives ▁way ▁to ▁ir r ational ▁buy ers ' ▁behavior ; ▁buy ers ▁bet ▁on ▁ever - in cre asing ▁demand ▁and ▁r ents ▁and ▁are ▁willing ▁to ▁pay ▁more ▁than ▁they ▁would ▁normally . ▁Will is ▁said ▁that ▁" height ▁is ▁a ▁bar ometer ▁of ▁bo om ", ▁" the ▁tall est ▁buildings ▁generally ▁appear ▁before ▁the ▁end ▁of ▁a ▁bo om , ▁their ▁height ▁driven ▁up ▁by ▁the ▁spec ulative ▁fe ver ▁that ▁affect s ▁both ▁developers ▁and ▁l enders ", ▁cit ing ▁cy clic ally ▁infl ated ▁land ▁values ▁as ▁the ▁principal ▁factor ▁for ▁increases ▁in ▁building ▁height , ▁but ▁did ▁not ▁elev ate ▁this ▁fact ▁to ▁become ▁an ▁" index ". ▁ ▁A ▁related ▁concept , ▁Sk ys cra per ▁Ind icator , ▁was ▁popular ized ▁by ▁Ralph ▁Nelson ▁Elli ott ▁in ▁the ▁ 1 9 3 0 s . ▁ ▁In ▁some ▁ways ▁this ▁appears ▁to ▁be ▁an ▁elabor ation ▁of ▁C . ▁North c ote ▁Park inson ' s ▁theory ▁that ▁only ▁organizations ▁in ▁decl ine ▁have ▁sle ek , ▁well - pl anned ▁buildings . ▁His ▁favorite ▁example ▁was ▁not ▁a ▁sk ys cra per , ▁but ▁the ▁city ▁of ▁New ▁Del hi ▁( part icular ly ▁the ▁area ▁now ▁referred ▁to ▁as ▁L ut yen ' s ▁Del hi ) ▁– ▁built ▁shortly ▁before ▁India ▁became ▁independent ▁of ▁the ▁British ▁build ers . ▁ ▁The ▁recently ▁constructed ▁Bur j ▁K hal ifa ▁may ▁join ▁this ▁list .