The theory of ‘temporary selection’ is concerned with the variation, for fixed x, of q[x–t]+t the observed rate of mortality at age x during the t+1th year after the issue of an assurance or annuity contract. The classical view is that—apart from chance variations—q[x–t]+t increases gradually with increasing t until the effects of selection have disappeared after which time q[xx–t]+t is a constant depending on x only.Various reasons have been suggested for the persistence of temporary selection in an observed series of values of q[xx–t]+t. The chief of these are:(1) The continuing effects of an initial selection on the part of the assurance company or by the annuitant (Morgan, 1834);(2) The gradual withdrawal from assurance of healthy lives (Higham, 1851); and(3) Secular improvements in medicals election or in the self-selection of annuitants (Karup, 1903).
Does the Revised Hukou System Facilitate or Restrain the Short-Term Labor Inflows into Chinese Cities?