Robert McCaa

Marriageways in Mexico and Spain, 1500–1900

How did formal marriage cohabitation and concubinage--what I call marriageways--differ between Spain and Mexico during the early modern period? The dissimilarities in ages at coupling and forms of cohabitation are much greater than previously suspected....After four centuries of extraordinary regional and racial differences in the frequency precocity and types of unions a single Mexican pattern of civil marriage emerged toward the middle of the twentieth century. It was preceded by an enormous profusion of types of unions fostered by the great inequalities of power between the sexes and social groups....In Spain the transition to a Western European pattern continued into the nineteenth century and beyond but as female age at marriage rose...so too did illegitimacy. European historians attribute these developments to urbanization rising economic opportunities for women and expanding sexual liberties. (SUMMARY IN FRE AND GER) (EXCERPT)

IPUMS-International high precision population census microdata samples: balancing the privacy-quality tradeoff by means of restricted access extracts

A breakthrough in the tradeoff between privacy and data quality has been achieved for restricted access to population census microdata samples. The IPUMS-International website, as of June 2006, offers integrated microdata for 47 censuses, totaling more than 140 million person records, with 13 countries represented. Over the next four years, the global collaboratory led by the Minnesota Population Center, with major funding by the United States National Science Foundation and the National Institutes of Health, will disseminate samples for more than 100 additional censuses. The statistical authorities of more than 50 countries have already entrusted microdata to the project under a uniform memorandum of understanding which permits researchers to obtain custom extracts without charge and to analyze the microdata using their own hardware and software. This paper describes the disclosure control methods used by the IPUMS initiative to protect privacy and to provide access to high precision census microdata samples.

Creating statistically literate global citizens: The use of IPUMS-International integrated census microdata in teaching

Census microdata are ideal for developing statistical literacy of university students. Access, particularly to internationally comparable microdata, has been a significant obstacle. The IPUMS-International project offers a uniform solution to providing access for policy analysts, researchers, and students to integrated microdata and metadata, while protecting statistical confidentiality. Eighty-five official statistical agencies have endorsed IPUMS-I dissemination principles and entrusted microdata for 249 censuses to the project. From June 2010, 159 integrated samples, representing 55 countries and totaling over 325 million person records, are available at no cost to researchers and their students. The database is being expanded with the addition of samples for 5-10 countries per year as well as samples for the 2010 round of censuses. This paper illustrates two approaches to using IPUMS-I census microdata in the university curriculum to promote statistical literacy among undergraduates.

When excessive perturbation goes wrong and why IPUMS-International relies instead on sampling, suppression, swapping, and other minimally harmful methods to protect privacy of census microdata

IPUMS-International disseminates population census microdata at no cost for 69 countries. Currently, a series of 212 samples totaling almost a half billion person records are available to researchers. Registration is required for researchers to gain access to the microdata. Statistics from Google Analytics show that IPUMS-Internationals lengthy, probing registration form is an effective deterrent for unqualified applicants. To protect data privacy, we rely principally on sampling, suppression of geographic detail, swapping of records across geographic boundaries, and other minimally harmful methods such as top and bottom coding. We do not use excessively perturbative methods. A recent case of perturbation gone wrong- the household samples of the 2000 census of the USA (PUMS), the 2003-2006 American Community Survey, and the 2004-2009 Current Population Survey-, an empirical study of the impact of perturbation on the usability of UK census microdata-the Individual SARs of the 1991 census of the UK-, and a mathematical demonstration in a timely compendium of statistical confidentiality practices confirm the wisdom of IPUMS microdata management protocols and statistical disclosure controls.

The Nahua calli of ancient Mexico: household, family, and gender

The Nahua (Aztecs) of ancient Mexico lived in large, extended family households (calli). A fundamental tenet of family history is that in the past high mortality was a major obstacle to household complexity. This was not the case for the Nahua, whose life expectancy was probably worse than any seen in Europe since the Black Death. Nahua populations were characterized by patriarchy, child marriage and greater proportions of complex and more diverse households than in regions of Europe which historians have identified as containing many complex households. Among the Nahua, although relationships within the household could be either uxorilocal or virilocal (relationship through the wife or the husband), subordination of women to male patriarchs was extensive. Most girls were married (cohabiting) well before the age of puberty. Thus, childless couples were common, but males without children rarely attained headship. While neither polygamy nor abandonment was widespread, their significance for gender oppression should not be denied. Widowhood offered new opportunities for companionship, but only for widowers. For widows, remarriage was infrequent and subordination to a male relative was inevitable. In modern Mexico, few remnants of this pre-conquest household system remain. According to the 1990 census, fewer than 10 per cent of Mexicans live as extended kin or as non-relatives in a household, even in rural Morelos where four centuries ago the compound family was the norm. The few modern examples of multiple family households tend to be Hispanic-like virilocal, patrilineal extended families.

Inverse Projection: Fine-Tuning and Expanding the Method

Inverse projection is a logical inversion of conventional projection techniques. Inverse projection uses crude data — annual totals of births and deaths and an estimate of initial population size — to infer refined demographic statistics — life expectancy, gross and net reproduction ratios, and even population age structures. Instead of deriving counts from age-specific rates as with conventional cohort projection, inverse projection estimates age-specific rates from counts. Where authentic age details for the initial population or age pattern of mortality are unavailable, model data usually yield acceptable results. The technique is particularly suited for studying populations of the past where age details are scarce.

Statistical coherence of primary schooling in population census microdata: IPUMS-International integrated samples compared for fifteen African countries.

The IPUMS-International project, now in its fifteenth year, integrates and disseminates population microdata for twenty-two African countries (82 countries world-wide) and the number continues to increase as more National Statistical Offices cooperate with the initiative. Statistical quality is a serious concern both for the producers of the microdata as well as the researchers who use them. This paper applies the intra-cohort comparison method to pairs of integrated (harmonized) samples for fifteen African countries to assess statistical coherence using as a benchmark the proportion completing primary school by single years of birth. Samples for six countries show near perfect coherence (R2 > .9, and regression coefficients ~1.0 +/- 0.6 <0.9). Large deviations from 1.0 characterize samples for only four countries. On the whole, the results suggest that samples for the fifteen countries have considerable utility for socio-demographic analysis.

IPUMS-international statistical disclosure controls: 159 census microdata samples in dissemination, 100+ in preparation

In the last decade, a revolution has occurred in access to census microdata for social and behavioral research. More than 325 million person records (55 countries, 159 samples) representing two-thirds of the worlds population are now readily available to bona fide researchers from the IPUMS-International website: www.ipums.org/international hosted by the Minnesota Population Center. Confidentialized extracts are disseminated on a restricted access basis at no cost to bona fide researchers. Over the next five years, from the microdata already entrusted by National Statistical Office-owners, the database will encompass more than 80 percent of the worlds population (85 countries, ~100 additional datasets) with priority given to samples from the 2010 round of censuses. A profile of the most frequently used samples and variables is described from 64,248 requests for microdata extracts. The development of privacy protection standards by National Statistical Offices, international organizations and academic experts is fundamental to eliciting world-wide cooperation and, thus, to the success of the IPUMS initiative. This paper summarizes the legal, administrative and technical underpinnings of the project, including statistical disclosure controls, as well as the conclusions of a lengthy on-site review by the former Australian Statistician, Mr. Dennis Trewin.

Demographic Techniques: Inverse Projection

Inverse projection is a logical inversion of conventional projection techniques. The method uses crude data—annual totals of births and deaths, and an estimate of initial population size—to infer refined demographic statistics—life expectancy, gross and net reproduction ratios, and even population age structures. Instead of deriving counts from age-specific rates, as with conventional cohort projection, inverse projection estimates age-specific rates from counts. Where authentic age details for the initial population or age pattern of mortality are unavailable, model data often yield acceptable results. The technique is particularly suited for studying populations of the past where age details are scarce.

Human Development Index-like Small Area Estimates for Africa Computed from IPUMS-International Integrated Census Microdata

Abstract This paper analyzes 24 African census samples from 13 countries available via the African Integrated Census MicroData website to illustrate how microdata may be used to assess development and pinpoint basic human needs at local administrative levels over time. We calculate a Human Development Index-like measure for small administrative areas, where much of the responsibility lies for executing policies related to health, education and general well-being. The methodological proposals introduced in this paper are particularly pertinent for the case of Africa. While it is true that data for much of Africa is not appropriate for economic growth rates or per-capita income estimates, the analysis in this paper demonstrates that they are good enough for many other purposes. Indeed, a major aggravating problem that contributes to the “African statistical tragedy” is the lack of accessibility to existing census microdata. This paper aims to illustrate the usefulness of census microdata—which are vastly under-utilized in Africa—and hopefully contribute to make them more transparent and freely accessible.