Validation of the 12 Item Short form Health Survey in a Sample from Region Central Jutland

In 2010 the Danish regions started a new program of public health surveillance in collaboration with the national and local health authorities using the short form health survey (SF-12) for measuring and reporting on health related quality of life among the Danish adult population. The instrument has not, however, been validated in a Danish setting. The aim of this study was to assess the reliability and validity of the physical component summary (PCS) and the mental component summary (MCS) score of the 12-item short form health survey (SF-12) in a sample from Central Denmark Region. A total of 26,397 persons above the age of 25 were included in the analyses. Reliability was assessed by Cronbach’s α. The validity was assessed using known-groups comparisons and convergent validity. The factor structure was investigated through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The Cronbach’s α showed high reliability with a score of 0.90 and 0.85 for PCS and MCS respectively. The SF-12 discriminated well with respect to gender, age, educational status and long term illness. Individual items correlated higher with own hypothesized scales than with other scales and summary measures corroborating the convergent validity. The EFA gave a two-factor structure. Irrespective of the chosen rotation method (varimax and oblimin) the items related to PCS loaded on one factor and the items related to MCS loaded on another factor. The factor structure was validated with acceptable model-fit values in CFA. The SF-12 instrument is a reliable and valid measure of health related quality of life among the population of Central Denmark Region.     

An assessment of the one-child policy in China from 1980 to 1985

An analysis of second and third live birth conceptions, from January 1980 to July 1984, in the two Chinese provinces of Hebei and Shaanxi from the In-Depth Fertility Surveys showed: (1) in urban areas third live birth conceptions were quite rare, and higher economic development was associated with lower second live birth conception risks; and (2) in the countryside the preference for sons was a strong predictor of both second and third live birth conceptions, and higher household income was followed generally by lower risks of second and third live birth conceptions, while other socioeconomic factors had little effect.Des enquêtes approfondies sur la fécondité de deux provinces chinoises de Hebei et Shaanxi ont porté sur la période s'étendant de janvier 1980 à juillet 1984. Une analyse des naissances vivantes de rangs deux et trois montre que: (a) dans les zones urbaines les naissances de range trois sont très rares; de même, plus le développement économique est élevé plus le risque de naissances de rang deux est bas; (2) dans les zones rurales la préférence pour les garçons permet de bien prévoir les naissances vivantes de rang deux et de rang trois; également un revenu plus élevé du ménage entraîne généralement moins de naissances de rangs deux et trois, tandis que d'autres facteurs socio-économiques ont une action négligeable sur cette fécondité.

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An earlier version of this paper was presented at the Annual Meeting of the American Sociological Association in San Francisco, August 9–13, 1989.     

A Forecast Model for Unemployment by Education

ABSTRACT We present a dynamic forecast model for the labour market: demand for labour by education and the distribution of labour by education among industries are determined endogenously with overall demand by industry given exogenously. The model is derived from a simple behavioural equation based on a strong relationship between the “strength” in the struggle for jobs of an educational group, and the change in relative supply. This relationship proves to be significant in the data. Furthermore, when used to forecast employment by education on real data, the model predicts reasonably well even for educational groups, where the initial forecast year is a change point for unemployment.     

Measuring sterility from incomplete birth histories

In this article, methods are presented for measuring the level and age pattern of sterility from incomplete birth histories, such as those that can be collected in demographic surveys of women who may not yet have reached the end of their reproductive span. The characteristics of the methods are examined in a simulation study that demonstrates that estimates based on information about fertility subsequent to a given age are more robust to variations in reproductive determinants, sample size, and sampling variation than the other measures, which include the frequently employed length of the open birth interval. In an illustrative analysis of World Fertility Survey data from sub-Saharan Africa, sterility was found to be high in Cameroon, intermediate in Lesotho and Sudan, and low in Ghana and Kenya relative to an English historical population.     

A Half Century of Mate Preferences: The Cultural Evolution of Values

The qualities people believe are important in selecting a marriage partner afford one domain for assessing human values. We examined the cultural evolution of these values over more than half a century. Building on existing data on mate preferences collected in 1939 (N= 628 ), 1956 (N= 120 ), 1967 (N= 566 ), and 1977 (N= 316 ), we collected data using the same instrument in 1984/1985 (N= 1,496 ) and in 1996 (N= 607 ) at geographically diverse locations. Several changes in values were documented across the 57‐year span. Both sexes increased the importance they attach to physical attractiveness in a mate. Both sexes, but especially men, increased the importance they attach to mates with good financial prospects. Domestic skills in a partner plummeted in importance for men. Mutual attraction and love climbed in importance for both sexes. The sexes converged in the ordering of the importance of different mate qualities, showing maximum similarity in 1996. Discussion speculates about causes of the cultural evolution of values.     

A non‐linear model of fecundability,postpartum amenorrhea,and sterility*

This paper proposes a convolution model of fecundability, controling for the effects of postpartum amenorrhea and unobserved heterogeneity in fecundability. Simulation analysis was used to assess the validity and reliability of estimates derived from the model. Analysis showed that the model captured the mean and standard deviation of age at the onset of sterility in simulated populations where sterility followed either a Gompertz, a gamma, or a lognormal distribution. The model performed well when sterility was specified by either a lognormal or a gamma distribution. The model also accurately estimated fecundability and postpartum amenorrhea. Next, the model was found to fit data from 17th and 18th century French Canadian birth histories. In this French Canadian sample the mean age at sterility was found to be 46.3 years using a gamma model. The decline in fecundability was almost linear after age 30. Thus, fecundability at age 40 had declined to about one‐third of that observed at age 30. Variability in individual fecundability was quite high. For example, women with fecundability one standard deviation above the mean had about 2.3 times as high fecundability as women one standard deviation below the mean.     

Strategic leadership in super-growth companies—a re-appraisal

This article reports on a research project to identify the attributes of high and super growth medium-size companies, the strategies they employ to maintain growth and the critical success factors they consider vital to achieve rapid growth.

Pronounced differences were found in the preferences between both groups when ranking seven critical success factors: (1) Flexibility; (2) Product diversification; (3) Attracting and holding quality staff; (4) Niche marketing; (5) Early entry into growth markets; (6) Quality; (7) and Frequent innovation. There were also differences in their strategic objectives, as well as, in the ages of the growth companies.     

Individual-level sterility: A new method of estimation with application to sub-saharan Africa

This paper extends work on measures of population proportions sterile to propose a new estimator of an individual woman's age at sterility and consequently her sterility status at given ages. Accuracy and reliability, examined in a simulation study, appear satisfactory. From World Fertility Survey data for five African countries, the proportions sterile by age estimated by the individual measure and by the population estimator are almost identical. Cameroon and Kenya show substantial variation in prevalence and incidence of sterility across ethnic groups and by number of marriages. Unexpectedly, the evidence suggests that sterility increased from 1960 on in Kenya and remained unchanged in Cameroon.