Micro and macro in long term population

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Population – the long view
Oxford, 16-17 September 2013
Micro and macro in long-term
population change
Francesco C. Billari
Department of Sociology and Nuffield College
University of Oxford
Outline
Some quotes (and scholars)
| Micro and macro demography
| Two stage approach
|
1. (Complex) description
z 2. Micro-founded
explanationÆintegrative view
z
Quote 1
|
Photo: www.thesun.co.uk
Coleman (2000): “I take
demography to be the statistical
study of the processes of
reproduction, migration and death
in the human species, their
interrelations with the distribution
and dynamics of population,and
their biological, environmental and
socio-economic causes and
consequences’’
Quote 1
Photo: www.thesun.co.uk
Quote 2
|
Preston, Heuveline, Guillot (2000):
“Demography is ‘the study of
population processes’ … (the
book) ‘attempts to impart an
understanding of the behavior of
human populations by describing
carefully the basic measures,
models, and observational
procedures devised by generations
of demographers”
Quote 3
|
Ron Lee (2001): “Key issues are
macrodemographic”, “Demography is changing in
profound ways, in its methods and topics of research,
and in its training. There is less aggregate level
(macro) analysis and more individual level (micro)
analysis. There is less emphasis on process and
dynamics, and more emphasis on individual
decisions about demographic behavior. There is less
formal demography, and more data analysis. There is
much less funding of aggregate demography and
formal demography, and much more funding of micro
level empirical studies.”
Micro and macro demography
|
Kuhn (1962)
Innovation in “normal science”
z Paradigm shift (“scientific revolution”)
z
Formal demography is the paradigm
(Vaupel: “births, deaths and
mathematics”)
| Still unsatisfactorily reconciled with
new approaches to explanation in the
social and natural sciences. We need
an integrative view
|
Stage 1 (complex) description
|
Goals
1.
2.
|
Documenting change (description)
Establishing the object of further
study (explananda)
Tools
z
z
Traditional measures (e.g., ageperiod-cohort specific rates and their
summaries)
New measures (micro-based):
sequence analysis
Traditional measures
TFR and e0 (Coale & Watkins,
1986)
Source: Livi Bacci (2012)
Traditional
measures: Lexis
Surfaces (Arthur
and Vaupel,
1984)
Source: Rau et al. (PAA, 2013).
Stage 1 (complex) description
|
Some threats when stopping at stage
1
Insularity—withdrawal from
comprehension and pure statistical
basis for prediction (expert-based
scenarios)
z Reification (Wilson & Oeppen, 2003)
z The challenge of “compositional
demography” (heterogeneity)
(Kreager, 2011)
z
New measures from micro data
Source: Bras et al., Demography (2010)
New measures from micro data
Source: Bras et al., Demography (2010)
Stage 2: explanation and/or
prediction
Life course approach (macroÆmicro)
| James Coleman’s boat
| Transformational mechanisms
(microÆmacro)
|
Life course (“micro” as the
outcome)—Giele & Elder
Coleman’s boat
Macro level
Situational
mechanisms (type
1)
Transformational
mechanisms (type 3)
Micro level
Action Formation
Mechanisms
(type 2)
Multiphasic change
“…an explanation of the
vigorous Japanese response
to sustained natural increase
must account for the
antagonism between such
increase and prosperity, in
terms of behavior prompted by
personal rather than national
goals.” (Davis, 1963)
Mortality
Vaupel, Manton & Stallard (1979) (see
also Perks, 1932).
| Macro level puzzle: declines and
reversals with age of differential
| Explananda: shape of aggregate-level
mortality rates
| Micro-macro
|
z
z
z
Aggregate-level force of mortality is an average
of individual-level force of mortality
If there is heterogeneity (frailty), frail individuals
tend to die first
Average frailty declines with age
Mortality
Mortality
Source: Vaupel, Nature (2010)
Migration
Schelling (1971) segregation model
| Macro level puzzle: racial segregation
in US cities
| Explanandum: segregation indices,
graphs
| Micro-macro
|
z
z
Choices to migrate depend on the composition of
the neighborhood
Also ‘tolerant’ micro-level preferences imply
macro-level segregation
Migration
Reproduction
Todd, Billari, Simão (2005) (see also
Billari, 2000)
| Macro level puzzle: micro-motivating
the shape of age at marriage
| Explanandum: shape of hazard of
marriage by age
| Micro-macro:
|
z
z
z
Fast-and-frugal search heuristics
Heterogeneity in search strategies
Agent-based modelling
Reproduction
Integrative view
We need an integrative view of
demography (see Goldthorpe on
sociology)
| Macro-level puzzles (complex
associations)
| Macro-micro-macro based
explanations and prediction
| Life course and formal demography
|
Integrative view
Macro level
Macro (complex)
descriptions
Situational
mechanisms (type
1)
Transformational
mechanisms (type 3)
Micro level
Action Formation
Mechanisms
(type 2)
Macro-->Micro-->Macro links (J.
Coleman+Goldthorpe)
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