[Forum SIS] Seminar ADRIAN RAFTERY

[Angela Montanari]

The Department of Statistical Sciences University of Bologna
is glad to announce the seminar

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Probabilistic Population Projections for All Countries

Adrian Raftery, University of Washington and University College Dublin

Monday October 28th 2013 11 a.m    Room III

Department of Statistical Sciences University of Bologna
Via Belle Arti 41

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Abstract: Projections of countries' future populations, broken down by age
and sex, are widely used for planning and research.
They are mostly done deterministically,
but there is a widespread need for probabilistic projections.
I will describe a Bayesian method for probabilistic population projections
for all countries.
The total fertility rate, female and male life expectancies at birth
are projected probabilistically using Bayesian hierarchical models
estimated via Markov chain Monte Carlo using UN population data for all
countries.
These are then converted to age-specific rates and combined with
a standard demographic projection model. This yields probabilistic
projections of any population quantity of interest.
These new statistical methods have been used by the United Nations to
produce their most recent population projections for all countries.

The results suggest that world population will increase more
than had recently been believed likely, reaching between 9 and 13 billion by
the end of the century, with no end to population growth this century.
The population of Africa, in particular, is likely to grow, from about
1 billion now to between 3 and 5 billion.
The results also indicate that the Potential Support Ratio
(roughly the number of working age people per retired person) will almost
certainly decline dramatically in most countries over the coming decades.
The results also suggest that the current UN high and low variants
underestimate uncertainty for high fertility countries, and overstate
uncertainty for low fertility countries, mostly in Europe.




Prof. Angela Montanari
Professor of Statistics
Department of Statistical Sciences 
University of Bologna
Via Belle Arti 41
40126 Bologna
tel:+390512098255