We propose a new model of knowledge creation in purposeful, loosely-coordinated, distributed systems, as an alternative to a firm-based one. Specifically, using the case of Linux kernel development project, we build a model of community-based, evolutionary knowledge creation to study how thousands of talented volunteers, dispersed across organizational and geographical boundaries, collaborate via the Internet to produce a knowledge-intensive, innovative product of high quality. By comparing and contrasting the Linux model with the traditional/commercial model of software development and firm-based knowledge creation efforts, we show how the proposed model of knowledge creation expands beyond the boundary of the firm. Our model suggests that the product development process can be effectively organized as an evolutionary process of learning driven by criticism and error correction. We conclude by offering some theoretical implications of our community-based model of knowledge creation for the literature of organizational learning, community life, and the uses of knowledge in society.

This program of prenatal and infancy home-visiting by nurses continued to improve the lives of women and children at child age 6 years, 4 years after the program ended.

This study examined the main and interactive effects of multiple social risk factors and the preschool child factors of IQ and mental health on students' academic trajectories from 1st grade to 12th grade. A multiple risk score summarizing 10 environmental risk factors was calculated at 4 years of age for 145 families. Hierarchical linear modeling showed that high-risk students had lower grades and more absences from 1st grade to 12th grade than did low-risk students. Significant interactions between risk and child factors for students' grade point average (GPA) revealed that child factors had significant effects only for low-risk students. Higher IQ and better mental health improved the GPA trajectories of low-risk children but did not influence the GPA trajectories of high-risk children.

This program of prenatal and early childhood home visitation by nurses can reduce the number of subsequent pregnancies, the use of welfare, child abuse and neglect, and criminal behavior on the part of low-income, unmarried mothers for up to 15 years after the birth of the first child.

This article describes a 20-year program of research on the Nurse Home Visitation Program, a model in which nurses visit mothers beginning during pregnancy and continuing through their children's second birthdays to improve pregnancy outcomes, to promote children's health and development, and to strengthen families' economic self-sufficiency. The results of two randomized trials (one in Elmira, New York, and the second in Memphis, Tennessee) are summarized, and an ongoing trial in Denver, Colorado, is briefly described. Results of the Elmira and Memphis trials suggest the following: The program benefits the neediest families (low-income unmarried women) but provides little benefit for the broader population. Among low-income unmarried women, the program helps reduce rates of childhood injuries and ingestions that may be associated with child abuse and neglect, and helps mothers defer subsequent pregnancies and move into the workforce. Long-term follow-up of families in Elmira indicates that nurse-visited mothers were less likely to abuse or neglect their children or to have rapid successive pregnancies. Having fewer children enabled women to find work, become economically self-sufficient, and eventually avoid substance abuse and criminal behavior. Their children benefitted too. By the time the children were 15 years of age, they had had fewer arrests and convictions, smoked and drank less, and had had fewer sexual partners. The program produced few effects on children's development or on birth outcomes, except for children born to women who smoked cigarettes when they registered during pregnancy. The positive effects of the program on child abuse and injuries to children were most pronounced among mothers who, at registration, had the lowest psychological resources (defined as high levels of mental health symptoms, limited intellectual functioning, and little belief in their control of their lives). Generally, effects in Elmira were of greater magnitude and covered a broader range of outcomes than in Memphis, perhaps because of differences between the populations studied, community contexts, or a higher rate of turnover among home visitors in Memphis than in Elmira. The article concludes that the use of nurses as home visitors is key; that services should be targeted to the neediest populations, rather than being offered on a universal basis; that clinically tested methods of changing health and behavioral risks should be incorporated into program protocols; and that services must be implemented with fidelity to the model tested if program benefits found in scientifically controlled studies are to be reproduced as the program is replicated in new communities.

Context.-A program of home visitation by nurses has been shown to affect the rates of maternal welfare dependence, criminality, problems due to use of substances, and child abuse and neglect. However, the long-term effects of this program on children's antisocial behavior have not been examined. Objective.-To examine the long-term effects of a program of prenatal and early childhood home visitation by nurses on children's antisocial behavior. Design.-Fifteen-year follow-up of a randomized trial. Interviews were conducted with the adolescents and their biological mothers or custodial parents. Setting.-Semirural community in New York. Participants.-Between April 1978 and September 1980, 500 consecutive pregnant women with no previous live births were recruited, and 400 were enrolled. A total of 315 adolescent offspring participated in a follow-up study when they were 15 years old; 280 (89%) were born to white mothers, 195 (62%) to unmarried mothers, 151 (48%) to mothers younger than 19 years, and 186 (59%) to mothers from households of low socioeconomic status at the time of registration during pregnancy. Intervention.-Families in the groups that received home visits had an average of 9 (range, 0-16) home visits during pregnancy and 23 (range, 0-59) home visits from birth through the child's second birthday. The control groups received standard prenatal and well-child care in a clinic. Main Outcome Measures.-Children's self-reports of running away, arrests, convictions, being sentenced to youth corrections, initiation of sexual intercourse, number of sex partners, and use of illegal substances; school records of suspensions; teachers' reports of children's disruptive behavior in school; and parents' reports of the children's arrests and behavioral problems related to the children's use of alcohol and other drugs. Results.-Adolescents born to women who received nurse visits during pregnancy and postnatally and who were unmarried and from households of low socioeconomic status (risk factors for antisocial behavior), in contrast with those in the comparison groups, reported fewer instances (incidence) of running away (0.24 vs 0.60; P = .003), fewer arrests (0.20 vs 0.45; P = .03), fewer convictions and violations of probation (0.09 vs 0.47; PϽ.001), fewer lifetime sex partners (0.92 vs 2.48; P = .003), fewer cigarettes smoked per day (1.50 vs 2.50; P = .10), and fewer days having consumed alcohol in the last 6 months (1.09 vs 2.49; P = .03). Parents of nurse-visited children reported that their children had fewer behavioral problems related to use of alcohol and other drugs (0.15 vs 0.34; P = .08). There were no program effects on other behavioral problems. Conclusions.-This program of prenatal and early childhood home visitation by nurses can reduce reported serious antisocial behavior and emergent use of substances on the part of adolescents born into high-risk families.

OBJECTIVE-Our goal was to test the effect of prenatal and infancy home visits by nurses on mothers' fertility and children's functioning 7 years after the program ended at child age 2.METHODS-We conducted a randomized, controlled trial in a public system of obstetric and pediatric care. A total of 743 primarily black women <29 weeks' gestation, with previous live births and at least 2 sociodemographic risk characteristics (unmarried, <12 years of education, unemployed), were randomly assigned to receive nurse home visits or comparison services. Primary outcomes consisted of intervals between births of first and second children and number of children born per year; mothers' stability of relationships with partners and relationships with the biological father of the child; mothers' use of welfare, food stamps, and Medicaid; mothers' use of substances; mothers' arrests and incarcerations; and children's academic achievement, school conduct, and mental disorders. Secondary outcomes were the sequelae of subsequent pregnancies, women's employment, experience of domestic violence, and children's mortality.RESULTS-Nurse-visited women had longer intervals between births of first and second children, fewer cumulative subsequent births per year, and longer relationships with current partners. From birth through child age 9, nurse-visited women used welfare and food stamps for fewer months. Nurse-visited children born to mothers with low psychological resources, compared with controlgroup counterparts, had better grade-point averages and achievement test scores in math and reading in grades 1 through 3. Nurse-visited children, as a trend, were less likely to die from birth through age 9, an effect accounted for by deaths that were attributable to potentially preventable causes.CONCLUSIONS-By child age 9, the program reduced women's rates of subsequent births, increased the intervals between the births of first and second children, increased the stability of their relationships with partners, facilitated children's academic adjustment to elementary school, and seems to have reduced childhood mortality from preventable causes.Address correspondence to David L. Olds, PhD, University of Colorado at Denver and Health Sciences Center, 1825 Marion St, Suite 200, Denver, CO 80218. olds.david@tchden.org. The authors have indicated they have no financial relationships relevant to this article to disclose. NIH Public Access Author ManuscriptPediatrics. Author manuscript; available in PMC 2010 March 16. Published in final edited form as:Pediatrics. Home visiting by nurses for low-income, at-risk families has been promoted as a promising strategy for preventing child abuse and neglect, children's mental health problems, 1-3 and infant mortality. 4 Recent evidence suggests that the benefits hoped for from such programs do not hold for all types of home-visiting programs. 5 A program of home visiting by nurses known as the Nurse-Family Partnership (NFP) has produced consistent effects on several aspects of maternal and child heal...

The presence of domestic violence may limit the effectiveness of interventions to reduce incidence of child abuse and neglect. JAMA. 2000;284:1385-1391.