Though windfall is usually associated with gain, here this
term is used to signify both unexpected gains and losses
through such events that are not expected, strike suddenly
and seem to be unavoidable.
positive index value signifies unexpected material gains
through inheritance or legacy, lost or hidden wealth, or
unearned easy gains in gambling, speculation and
negative index value signifies the reverse - all type of
calamities and losses in speculation & gambling,
defeat or insult, severe mental sorrow, hindrances,
disgrace and loss of material.
'Index of Sudden gains' have some common significations,
'Windfall Index' incorporates more 'element of surprise'