12.12.2012 Views

rivista italiana di economia demografia e statistica - Sieds

rivista italiana di economia demografia e statistica - Sieds

rivista italiana di economia demografia e statistica - Sieds

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

12<br />

Volume LXV n. 1 – Gennaio-Marzo 2011<br />

Two of the models proposed achieve a better fit over the “accidental bump”<br />

region at the cost of ad<strong>di</strong>ng one more parameter to the second component.<br />

Moreover, in order to gain more flexibility in modeling mortality at older ages, two<br />

models employ, as third component, a logistic function with the same number of<br />

parameters used by the exponential form in the Heligman-Pollard model.<br />

In conclusion we believe that the proposed models may offer a valuable<br />

alternative to the classical Heligman-Pollard model, especially when there is the<br />

need of more flexibility to model death rates at the accidental bump or at older<br />

ages.<br />

_____________________<br />

Anna Maria ALTAVILLA, Or<strong>di</strong>nario <strong>di</strong> Demografia, Università <strong>di</strong> Catania.<br />

Angelo MAZZA, Ricercatore <strong>di</strong> Statistica, Università <strong>di</strong> Catania.<br />

Antonio PUNZO, Assegnista <strong>di</strong> Ricerca in Statistica, Università <strong>di</strong> Catania.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!