1、Calibrating Census Microdata ALAS, Comisin No. 8, Mesa 7a ver 10/10/01 p. 1Women in the workforce: calibrating census microdata against a gold standardMexico, 1970, 1990 and 2000Robert McCaa, Rodolfo Gutirrez and Gabriela Vsquez1University of Minnesota Population Center (rmccaaumn.edu)XXIII CONGRESO
2、 DE LA ASOCIACIN LATINOAMERICANA DE SOCIOLOGA (ALAS)Antigua,Guatemala: Oct. 29-Nov 2, 2001Comisin no. 8 Cambio Demogrfico, Migraciones y FamiliaCalibrate, v. 1864. a. trans. To determine the calibre of; spec. to try the bore of a thermometer tube or similar instrument, so as to allow in graduating i
3、t for any irregularities: to graduate a gauge of any kind with allowance for its irregularities.The Oxford English Dictionary Online (Oxford: Clarendon Press, 2001).Introduction. According to the 1990 national census, the global labor force participation rate for Mexican females aged 12-64 was 20.6%
4、. 34.8% was the figure reported by the national urban employment survey taken during the same quarter. From a simple comparison of these global figures the census was dismissed as inaccurate, and over the ensuing decade neither the published census tables nor the census microdata sample of individua
5、ls was much used to study the economic position of Mexican women (Vsquez, Gutirrez and McCaa, 2000). The 2000 census data are now available and a glaring disparity between the global figures for the census and survey remains, notwithstanding remarkable efforts by Mexican census officials to improve
6、the quality of reporting on females in the workforce. The apparent disparity for 1990 of 14.2 percentage points is reduced by only 3.8 to 10.4 for 2000. While the rate in the census had risen by more than one-half to 32.9%, the survey figure soared, reaching 41.7%. Before the 2000 data on female lab
7、or suffers the same neglect as those for 1990, detailed scrutiny of the census microdata is called for. The real difference in 2001 shrinks to an insignificant 1.5 percentage points, by simply controlling for sampling frame, as this paper will demonstrate. A decade earlier the real disparity was onl
8、y 5.8, when the census figure is computed for the sixteen cities covered by the urban employment survey (Jusidman and Eternod 1995:9 place the disparity at 5.5). The purpose of this paper is to calibrate the Mexican census microdata for 1990 and 2000 using urban employment surveys as “gold standards
9、“. The IPUMS International project proposes to integrate census microdata samples of individuals, households and dwellings, including those of Mexico for 1960, 1970, 1990 and 2000, and to disseminate them freely over the web to bona-fide users who sign a non-disclosure agreement. If the data are to
10、be used well, not only must they be fully documented they must also be calibrated against the best sources available. Of all census statistics, female labor activity is widely regarded as one of the most severely challenged, or biased. Because of the withering criticisms of the 1990 census as a tool
11、 for gauging womens economic activity in Mexico (Garcia 1994b, Jusidman and Eternod 1995, Garca Guzmn, Blanco Snchez and Gmez Muoz 1999; Pedrero Nieto 2000), the topic offers a strong test for calibration. This paper shows that the perceived flaws in the Mexican censuses are more apparent than real.
12、 Much of the difference between censuses and urban employment surveys in measuring female labor activity can be explained away by controlling for sampling frame (metropolitan residence) and three structural variables-age, marital status, and educational attainment. In 1990 the employment survey was
13、limited to sixteen metropolitan areas (generally cities with 500,000 inhabitants or more, including Mexico City, Guadalajara, Monterrey, Puebla, Len, Torren, San Lus Potos, Mrida, Chihuahua, Tampico, Orizaba, Veracruz, Ciudad Jurez, Tijuana, Matamoros, and Nuevo Laredo, but not Cuernavaca or Culiacn
14、 which also numbered more than one-half million). When the “global“ figure from the 1990 1Research for this paper was funded by Grant SBR-9908380 from the National Science Foundation. We thank Matt Sobek for making available to us his historical census microdata series on women in the United States
15、labor force.Calibrating Census Microdata ALAS, Comisin No. 8, Mesa 7a ver 10/10/01 p. 2census microdata is recomputed for metropolitan areas, the disparity is more than halved to 5.8 percentage points. For 2000, the disparity shrinks by almost nine-tenths to only 1.5, a modest error by any measure.
16、If one focuses on hours worked or income, even the conventional definition captures most of the economic work women do. The Mexican census microdata on female labor force participation are of exceedingly high quality in 2000. For 1990 the census question was indeed flawed to an unfortunate degree. T
17、he word “principal“ was inserted before “activity“ which led to substantial under-reporting by homemakers and students. Yet, even the 1990 census microdata sample can be made to reveal valuable insights on the evolution of the place of women in the Mexican workforce. In general, researchers accustom
18、ed to dismissing the census as inadequate and unreliable are encouraged to reconsider what to many is a new and, until now, difficult to obtain source, census microdata. For many countries, including Mexico, census microdata are the only source of truly national scope and of sufficient sample size t
19、o sustain complex models, as well as the only continuous indicator comparable over decades. Indeed, as this paper will suggest, it is essential to calibrate survey data of all kinds using census microdata as a benchmark, if not a gold standard, so that the strengths and weaknesses of some of the mos
20、t commonly used sources in the social sciences may be adequately gauged.this study shows the vast analytical possibilities of the census sample, which in spite of being only one percent, is of a size several times larger than surveys. It is the source of choice to explore complex hypotheses which re
21、quire a great mass of data.Crtes Cceres and Rubacalva Ramos (1994, 56)Reality check. The Integrated Public Use Microdata Series International project (IPUMSi) proposes to deliver census samples of individuals and households integrated according to uniform standards for a dozen or more countries and
22、for all available censuses. For most countries, such as Mexico where the first sample was for the 1960 enumeration, census microdata series cover the last decades of the twentieth century. Are census microdata of sufficient quality to be usable? Given the complexities of census concepts and cultural
23、 variations between countries, researchers might question the feasibility of attempting to harmonize census samples overtime and even more so between countries. As a matter of professional responsibility, making census microdata available to a broader range of users demands that the providers offer
24、guidelines on the limits of the data. With respect to womens work, we are spurred on, in part, by recent research emphasizing the benefits to be gained by comparative analysis based on census data (Schultz 1990). Then too, it is precisely at the microdata level where prospects for harmonization are
25、best. Here a variety of controls and checks may be taken into account at the individual level to overcome disparities that are impossible to remove from published tables. This preliminary reality check is not based on integrated data. These will be constructed only after careful study by Mexican exp
26、erts.2 Once comprehensive documentation is in hand, the Mexican team will design the integration. Only then can the raw census microdata be programmed, variable-by-variable, code-by-code, census-by-census, and country-by-country. For this paper we “harmonize“ the necessary variableslabor force parti
27、cipation, age, marital status, educational attainment, and size of place of residencefor each dataset separately. Then, the sets are tabulated and combined for the multi-variate analysis with both source (census, employment survey) and time (1990 and 2000) as variables. Finally the Mexican census mi
28、crodata on female labor force are compared with a newly integrated, century-long historical series for the United States, also developed from census microdata.3 Mexican census data are not held in high regard by economists and demographers. For population historians on the other hand, accustomed to
29、working with less than perfect information, the Mexican census samples constitute an enticing source. They are the largest, richest datasets available for the study of the Mexican population in the last decades of the twentieth century (Table 1). From 1960 at regular decennial intervals, they provid
30、e the only comparable data over any extended chronological 2 The team is made up of: Cecilia Rabell Romero, Marta Mier y Tern, Virgilio Partida Bush, Marco Antonio Ramirez Mocarro, Rodolfo Corona, Ddimo Castillo, Marcela Eternod, Susan De Vos, and the authors of this paper.3Sobek (1997:58-113) offer
31、s an insightful, comprehensive analysis of the shortcomings of census enumerations of the United States on women in the labor force and how for more than a century census officials and scholars have proposed to overcome them.Calibrating Census Microdata ALAS, Comisin No. 8, Mesa 7a ver 10/10/01 p. 3
32、period. Most sample surveys fail to maintain consistent coverage, questions, or phrasing for longer than a decade or two. Few pretend to attain truly national coverage, not even the so called “national” urban employment survey, which in 1990 covered only sixteen metropolitan areas, now expanded to f
33、orty-seven. “Smaller” places where three-fourths of the population resided were outside the 1990 sampling frame. Census microdata usually do not have these shortcomings. They constitute nationally representative samples. Indeed for the 2000 census, to assure tolerable sampling errors for all but the
34、 smallest municipalities, a dense, sophisticated design was used, yielding over ten million cases, or ten percent of the population. For historians interested in long-term change, the Mexican census microdata are intriguing because many of the concepts in the censuses remain remarkably constant over
35、 decades. Although questions about employment are modified at least slightly from one census to another (Altimir 1974, Kessing 1977, Morelos 1993, Garca 1994a), there is remarkable consistency both in content and quality of coverage between the censuses of 1970, 1990 and 2000. In contrast, the censu
36、ses of 1960 and 1980 are generally regarded as of lower quality and not as uniform (Morelos 1972, Garca 1973, Altimir 1974, Kessing 1977, Rendn and Salas 1986, 1987, Morelos 1993, Garca 1994a, Jusidman and Eternod 1995). Table 1. Selected microdata samples of Mexico, 1960 - 2000Year Sample Size Dens
37、ity (% of total population)Census Microdata1960 502,702 1.51970 480,265 1.01990 802,774 1.02000 10,099,182 10.0National urban employment survey (quarterly since 1987)1990 172,233 0.22000 562,471 0.6Note: Employment surveys cited here are for the first quarter of the year. No sample was drawn for the
38、 1980 census due to losses caused by the 1985 earthquake.In the censuses of 1970 and 1990, the economically active population was defined as anyone who had realized at least one hour of economic activity in the week preceding the census in exchange for remuneration, salary, or payment in money or ki
39、nd. The definition specifically includes individuals who were temporarily out of work for any reason or who worked without pay for a family enterprise or as an apprentice or trainee. Both censuses consistently coded under distinct rubrics homemakers, students, and the retiredthat is, those who impli
40、citly answered “no” to all the work categoriesso these important sub-groups of the population may be analyzed separately. Both censuses were conducted during slow months in the agricultural cycle, but the fact that the 1970 census occurred in January and the 1990 in March may be unsettling to some r
41、esearchers. The 2000 enumeration was carried out in late February and sought to verify activity by adding a question which probed more deeply than any previous census. Since 1970 the basic labor activity question offers eight options, in the following order: worked, looked for work, looked for work
42、for the first time, studied, kept house, was retired, disabled, or other. In addition, the 1970 schedule requested number of weeks worked during the previous year, and the 1990 and 2000 enumerations requested the number of hours worked in the past week. Both questions permit more scrutiny of the mic
43、rodata than published tables allow. The long-form for the 2000 census of Mexico includes new or expanded modules on economic activity as well as migration, health insurance, education, and income. The labor force module is Calibrating Census Microdata ALAS, Comisin No. 8, Mesa 7a ver 10/10/01 p. 4ex
44、panded to two questions: “condition of activity“ and “verification of condition“ (Table 2). The first question is identical to the lay-out for 1990, with the exception that on the 2000 form there is no time referent (“one hour“ in 1990) and the word “principal“ was omitted. The 1990 enumeration form
45、 prefixed the word “principal“ to “activity“ for the first, and hopefully the last time in the history of Mexican census taking. Inserting that word has the unfortunate effect of filtering out homemakers, students, and others for whom economic activity was secondary. Table 2. Counting the economical
46、ly active female population: censuses and urban employment surveys for 1990 and 2000 compared (data in percent)1990 2000Category Survey Census Survey CensusHeading on form - Principal activity- Condition of activityPeriod of reference 1 hour last week1 hourlast week1 hour last weeklast weekWorked in
47、 reference period 28.7 19.8 36.7 27.5Had worked 1.4 0.3 2.5 0.4Looked for work 0.8 0.5 1.1 0.3Verification questionsSearched for work - - - 0.0Student who worked - - - 0.5Housewife who worked - - - 3.7Retired who worked - - - 0.0Other who worked - - - 0.4No reply but verfication reveals that worked-
48、 - - 0.0Helped in non-family business without pay 0.0 - 0.0 -Helped in family business without pay 2.5 - 1.1 -Did not work, but was paid 1.8 - 1.7Will return to work or begin to work (active if less than 4 weeks)?0.2 - 0.2 -Global female activity rate (%)* 34.6 20.6 43.3 32.916 cities global female
49、activity rate (%) 34.6 29.0 41.7 40.2Females aged 12-64 years (n) 62,248 269,306 166,582 3,431,89216 cities as in ENEU 1990 (n) 62,248 63,929 124,051 951,042*may not sum due to rounding.Sources: Instituto Nacional de Estdistica, Geografa e Informtica. Encuesta Nacional de Empleo Urbano (ENEU), Aguascalientes: 1990 and 2000 (microdata samples for first quarter of respective years); Cdice 90: Muestra del uno porciento del XI censo de poblacin, 1990, Aguascalientes: 199
