Nicholas A Christakis
Biographic Data
| ID | 85667 |
|---|---|
| NAME | Nicholas A Christakis |
| GIVEN NAMES | Nicholas A |
| FAMILY NAME | Christakis |
| SIGNATURE | CHRISTAKIS N A |
| AFFILIATIONS | Yale University |
| ORCID | 0000-0001-5547-1086 |
| VERIFIED | Yes |
| TOTAL WORKS | 92 |
| TOTAL CITATIONS | 1061 |
| AUTHOR COUNT | 92 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1985 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 18 |
The Influence “Paradox”: When More Network Ties Lead to Less Change
The diffusion of behaviors and ideas is a core concern in many fields and highly relevant to collective action and innovation adoption. A common assumption is that well-connected individuals within social networks are especially influential and so are good targets to initiate behavioral interventions. Here, we argue that the effectiveness of network-based targeting depends on how social ties are organized within a network. We theorize that there …
Countering the forgetting of novel health information with ‘social boosting’
The prevalence of misleading information, especially with respect to health care practices, poses a threat. While studies have shown the effectiveness of various intervention techniques in mitigating the adverse effects of low-quality or false information, the effectiveness of such interventions can decay. Here, we investigate the role of the detailed social structure within which the intervened individuals live, which provides opportunities for …
Cognitive representations of social networks in isolated villages
Systematic review of methods to discern antagonistic ties in social networks in community settings
Human social networks are naturally signed, including both positive and negative ties. However, the instruments for appraising negative ties are less established than those focusing on positive, friendly connections. An improved consensus on useable instruments could support the comparability, reliability, and validity of measures used to map social networks involving negative ties. This methodological systematic review summarizes and classifies …
AI and the transformation of social science research
Careful bias management and data fidelity are key
Mass gatherings for political expression had no discernible association with the local course of the Covid-19 pandemic in the USA in 2020 and 2021
Reprint of: Using Trellis software to enhance high-quality large-scale network data collection in the field
Using Trellis software to enhance high-quality large-scale network data collection in the field
Trellis is a mobile platform created by the Human Nature Lab at the Yale Institute for Network Science to collect high-quality, location-aware, off-line/online, multi-lingual, multi-relational social network and behavior data in hard-to-reach communities. Respondents use Trellis to identify their social contacts by name and photograph, a procedure especially useful in low-literacy populations or in contexts where names may be similar or confusing…
Household food insecurity and health in a high-migration area in rural Honduras
Household food insecurity (HFI) is a significant problem in the developing world. Relationships between HFI and nutrition, physical growth, and development have been elucidated; less is known about the non-nutritional impacts among individuals living in rural areas in low-income countries. The aim of this study was to determine if HFI is a risk factor for suboptimal mental health and overall health in rural Honduras. In a population of 24,696 adu…
Population flow drives spatio-temporal distribution of Covid-19 in China
Social normative and social network factors associated with adolescent pregnancy: A cross-sectional study of 176 villages in rural Honduras
BACKGROUND: Adolescent pregnancy and childbirth are common throughout Central America. While gendered beliefs promoting motherhood are a known risk factor, their association with adolescent childbirth within the social networks of Central American communities is unknown. METHODS: This was a cross-sectional study looking at adolescent childbirth amongst women ages 15-20 years (N = 2990) in rural Honduras, using reproductive health data on all indi…
Lack of sexual behavior disclosure may distort STI testing outcomes
Sexual behavior and outness may affect gonorrhea and chlamydia testing provision. Apart from clinicians, community based efforts may reduce stigma based barriers to testing
Machine behaviour
Do village-level normative and network factors help explain spatial variability in adolescent childbearing in rural Honduras
Adolescent childbearing rates are higher in Central America than almost anywhere else. However, in this research we discovered that adolescent childbearing exhibits variability from one village to another, and we might discover factors associated with this spatial variability that can help us understand key characteristics underlying the pattern of early childbearing. To do this, we assessed the village-level normative and network factors associa…
The Structure of Negative Social Ties in Rural Village Networks
Negative (antagonistic) connections have been of longstanding theoretical importance for social structure. In a population of 24,696 adults interacting face to face within 176 isolated villages in western Honduras, we measured all connections that were present, amounting to 105,175 positive and 16,448 negative ties. Here, we show that negative and positive ties exhibit many of the same structural characteristics. We then develop a complete taxono…
Association Between Degrees of Separation in Physician Networks and Surgeons’ Use of Perioperative Breast Magnetic Resonance Imaging
BACKGROUND: Perioperative magnetic resonance imaging (MRI) is frequently used in breast cancer despite unproven benefits. It is unclear whether surgeons' use of breast MRI is associated with the practices of other surgeons to whom they are connected through shared patients. METHODS: We conducted a retrospective study using Medicare data to identify physicians providing breast cancer care during 2007-2009 and grouped them into patient-sharing netw…
The social network context of HIV stigma: Population-based, sociocentric network study in rural Uganda
Social network correlates of IPV acceptance in rural Honduras and rural Uganda
We investigated the household-level social network correlates of acceptance of intimate partner violence (IPV) in rural, agrarian settings of Honduras and Uganda, two low-income countries with unequal access to resources based upon gender. We collected complete social network data in each location (Honduras in 2014 and Uganda in 2012), across a diverse range of relationships, and then created a measure of household cohesion by calculating the deg…
Food insecurity, social networks and symptoms of depression among men and women in rural Uganda: A cross-sectional, population-based study
Objective To assess the association between food insecurity and depression symptom severity stratified by sex, and test for evidence of effect modification by social network characteristics. Design A population-based cross-sectional study. The nine-item Household Food Insecurity Access Scale captured food insecurity. Five name generator questions elicited network ties. A sixteen-item version of the Hopkins Symptom Checklist for Depression capture…
The “average” treatment effect: A construct ripe for retirement. A commentary on Deaton and Cartwright
Cyclic motifs in the Sardex monetary network
An exploratory comparison of name generator content: Data from rural India
Actual Versus Perceived HIV Testing Norms, and Personal HIV Testing Uptake: A Cross-Sectional, Population-Based Study in Rural Uganda
Intimate partner violence norms cluster within households: An observational social network study in rural Honduras
Our results show that differential targeting of individuals and relationships in order to reduce the acceptability and, subsequently, the prevalence of IPV may be most effective. Because IPV norms seem to be strongly held within households, the household is probably the most logical unit to target in order to implement change. This approach would include the possible benefit of a generational effect. Finally, in social contexts in which perpetrat…
Polio vaccine hesitancy in the networks and neighborhoods of Malegaon, India
Social Networks and Health
People are interconnected, and so their health is interconnected. In recognition of this social fact, there has been growing conceptual and empirical attention over the past decade to the impact of social networks on health. This article reviews prominent findings from this literature. After drawing a distinction between social network studies and social support studies, we explore current research on dyadic and supradyadic network influences on …
Alone in the crowd: The structure and spread of loneliness in a large social network
The discrepancy between an individual's loneliness and the number of connections in a social network is well documented, yet little is known about the placement of loneliness within, or the spread of loneliness through, social networks. The authors use network linkage data from the population-based Framingham Heart Study to trace the topography of loneliness in people's social networks and the path through which loneliness spreads through these n…
Widowhood and Race
The health effects of marital status are frequently cited in the current debate on marriage promotion, but little is known about how marital health effects vary across groups. This article assembles the largest properly longitudinal and nationally representative dataset of elderly married couples in the United States (N = 410,272 couples) and provides strong evidence that the "widowhood effect"-how the death of a spouse increases the mortality of…
Widowhood Effects in Voter Participation
Past research suggests that spouses influence one another to vote, but it relies almost exclusively on correlation in turnout. It is therefore difficult to establish whether spouses mobilize each other or tend to marry similar others. Here, we test the dependency hypothesis by examining voting behavior before and after the death of a spouse. We link nearly six million California voter records to Social Security death records and use both coarsene…
Effect of specific aspects of community social environment on the mortality of Individuals diagnosed with serious illness
Logit Models for Sets of Ranked Items
Methods are presented for analyzing data generated by asking respondents to rank a set of items. Based on a conditional logit model, these methods allow us to estimate and test for differences among items in respondents' preferences for them; to test for differences in item preferences across subpopulations; and to incorporate predictor variables describing respondents, items, or both. The models can be easily estimated with programs for proporti…
Friendships Moderate an Association between a Dopamine Gene Variant and Political Ideology
Scholars in many fields have long noted the importance of social context in the development of political ideology. Recent work suggests that political ideology also has a heritable component, but no specific gene variant or combination of variants associated with political ideology have so far been identified. Here, we hypothesize that individuals with a genetic predisposition toward seeking out new experiences will tend to be more liberal, but o…
The Taste for Privacy: An Analysis of College Student Privacy Settings in an Online Social Network
The rapid growth of contemporary social network sites (SNSs) has coincided with an increasing concern over personal privacy. College students and adolescents routinely provide personal information on profiles that can be viewed by large numbers of unknown people and potentially used in harmful ways. SNSs like Facebook and MySpace allow users to control the privacy level of their profile, thus limiting access to this information. In this paper, we…
Social Network Concordance in Food Choice Among Spouses, Friends, and Siblings
Objectives. We investigated whether eating behaviors were concordant among diverse sets of social ties. Methods. We analyzed the socioeconomic and demographic distribution of eating among 3418 members of the Framingham Heart Study observed from 1991 to 2001. We used a data-classification procedure to simplify choices into 7 nonoverlapping patterns that we matched with information on social network ties. We used correlation analysis to examine eat…
The Effect of Widowhood on Mortality by the Causes of Death of Both Spouses
Objectives. We investigated the effect of spousal bereavement on mortality to document cause-specific bereavement effects by the causes of death of both the predecedent spouse and the bereaved partner. Methods. We obtained data from a nationally representative cohort of 373 189 elderly married couples in the United States who were followed from 1993 to 2002. We used competing risk and Cox models in our analyses. Results. For both men and women, t…
Ethics are local: Engaging cross-cultural variation in the ethics for clinical research
Fixed-Effects Methods for the Analysis of Nonrepeated Events
For repeated events, fixed-effects regression methods—which control for all stable covariates—can be implemented by doing Cox regression with stratification on individuals. For nonrepeated events, we consider the use of conditional logistic regression to estimate fixed-effects models with discrete-time data. Known in the epidemiological literature as the case-crossover design, this method fails when any covariate is a monotonic function of time. …
The health impact of health care on families: A Matched Cohort Study of Hospice Use by Decedents and Mortality Outcomes in Surviving, Widowed Spouses
Income inequality and weight status in US metropolitan areas
Marriage, widowhood, and health-care use
Medical modelling of obesity: A transition from action to experience in a 20th century American medical textbook
Obesity is now the focus of considerable attention in the medical profession, and many have noted that obesity has been progressively medicalised. The subjection of phenomena to medical explanation, however, has been associated with both the potential to relieve and also to exacerbate the attribution of individual responsibility. In order to understand the ways in which a particular phenomenon, obesity, can be variously conceptualised at differen…
Widowhood and mortality among the elderly: The modifying role of neighborhood concentration of widowed individuals
Social network predictors of latrine ownership
Wives and ex-wives: A new test for homogamy bias in the widowhood effect
Increased mortality following the death of a spouse (the “widowhood effect”) may be due to (1) causation, (2) bias from spousal similarity (homogamy), or (3) bias from shared environmental exposures. This article proposes new tests for bias in the widowhood effect by examining husbands, wives, and ex-wives in a longitudinal sample of over 1 million elderly Americans. If the death of an ex-wife has no causal effect on the mortality of her husband,…
Effects of Proximate Foreclosed Properties on Individuals’ Weight Gain in Massachusetts, 1987–2008
Objectives. We assessed the extent to which living near foreclosed properties is associated with individuals’ subsequent weight gain. Methods. We linked health and address information on 2068 Framingham Offspring Cohort members (7830 assessments) across 5 waves (1987–2008) to records of all Massachusetts foreclosures during that period. We used counts of lender-owned foreclosed properties within 100 meters of participants’ homes to predict body m…
Physician characteristics associated with decisions to withdraw life support
OBJECTIVE. This study was undertaken to identify attributes of physicians associated with physicians' decisions to withdraw life support. METHODS. Of the 862 Pennsylvania internists surveyed and asked to make decisions in response to hypothetical vignettes and to report their actual experience with the withdrawal of life support, 485 (56%) responded. The data were analyzed with regression models. RESULTS. With other factors controlled, physicians…
Associations of Environmental Factors With Elderly Health and Mortality in China
Objectives. We examined the effects of community socioeconomic conditions, air pollution, and the physical environment on elderly health and survival in China. Methods. We analyzed data from a nationally representative sample of 15 973 elderly residents of 866 counties and cities with multilevel logistic regression models in which individuals were nested within each county or city. Results. After control for individual-level factors, communities'…
Polio vaccine hesitancy in the networks and neighborhoods of Malegaon, India
A methodology for identifying married couples in medicare data: Mortality, morbidity, and health care use among the married elderly
Wedescribe a method for the development of cohorts of up to three quarters of the 14 million married couples aged 65 and over in the United States. The health care experiences, illness histories, and mortality of these identified couples can be assessed longitudinally using Medicare data. We summarize strengths and limitations of using data from Medicare administrative records for the study of marriage, health, and aging. We illustrate the method…
The ellipsis of prognosis in modern medical thought
Do Medical Student Research Subjects Need Special Protection
In 1956 the faculty of Harvard Medical School instituted carefully formulated regulations governing the use of medical students as research subjects. The regulations established several echelons of review for projects involving students, a class of subjects for whom the faculty felt it had a special responsibility. No such extra consideration was granted to other adult participants in research. The regulations, issued in a memorandum entitled Rul…
The Limits of Science in On-The-Job Drug Screening
Mass drug screening offers a deceptively simple solution to the\nproblem of drug use among workers. Even a very effective test is subject to\nerror. In any given group of tested individuals, some will unavoidably be\nfalsely accused. Even though scientific tests appear to provide efficient\nsolutions to social and legal problems, these tests should not be accepted\nunless they also meet our standards for fair dealing
Baby Fae and the Media: How the Law Allows Appropriate Access
The Ethical Design of an Aids Vaccine Trial in Africa
Proper conduct of an AIDS vaccine trial in Africa must be informed\nnot only by the epidemiology and biology of HIV infection in African settings,\nbut also by the ethical norms and cultural constraints prevailing in African\nsettings
Should IRBs Monitor Research More Strictly
Clinical Aids Research That Evaluates Cost Effectiveness in the Developing World
Nicholas A. Christakis, Lorna A. Lynn, Aduato Castelo, Clinical AIDS Research That Evaluates Cost Effectiveness in the Developing World, IRB: Ethics & Human Research, Vol. 13, No. 4 (Jul. - Aug., 1991), pp. 6-8
Ethics are local: Engaging cross-cultural variation in the ethics for clinical research
Logit Models for Sets of Ranked Items
Methods are presented for analyzing data generated by asking respondents to rank a set of items. Based on a conditional logit model, these methods allow us to estimate and test for differences among items in respondents' preferences for them; to test for differences in item preferences across subpopulations; and to incorporate predictor variables describing respondents, items, or both. The models can be easily estimated with programs for proporti…
Physician characteristics associated with decisions to withdraw life support
OBJECTIVE. This study was undertaken to identify attributes of physicians associated with physicians' decisions to withdraw life support. METHODS. Of the 862 Pennsylvania internists surveyed and asked to make decisions in response to hypothetical vignettes and to report their actual experience with the withdrawal of life support, 485 (56%) responded. The data were analyzed with regression models. RESULTS. With other factors controlled, physicians…
Why Do Physicians Prefer to Withdraw Some Forms of Life Support over Others: Intrinsic Attributes of Life-Sustaining Treatments Are Associated with Physicians' Preferences
Some physicians caring for critically ill patients have preferences for withdrawing some forms of life support over others, even after the decision to withdraw life support has already been made. Past research has attempted to explain these preferences by variations in clinical circumstances. The authors wondered whether differences in the forms of life support themselves might be important, and whether these differences would reveal implicit goa…
The ellipsis of prognosis in modern medical thought
A methodology for identifying married couples in medicare data: Mortality, morbidity, and health care use among the married elderly
Wedescribe a method for the development of cohorts of up to three quarters of the 14 million married couples aged 65 and over in the United States. The health care experiences, illness histories, and mortality of these identified couples can be assessed longitudinally using Medicare data. We summarize strengths and limitations of using data from Medicare administrative records for the study of marriage, health, and aging. We illustrate the method…
Conducting Physician Mail Surveys on a Limited Budget: A Randomized Trial Comparing $2 Bill Versus $5 Bill Incentives
OBJECTIVES: The effects of incentive size on physicians' response rates to a mail survey were determined. METHODS: One thousand US primary care physicians were assigned randomly to receive a survey with either a $5 bill or a $2 bill as an incentive. For each of the two incentive groups, the overall response rate for three mailing waves, the total cost, and the total cost per usable response were measured. RESULTS: The response rate among those re…
The Performance of Different Lookback Periods and Sources of Information for Charlson Comorbidity Adjustment in Medicare Claims
BACKGROUND: The Charlson Score is a particularly popular form of comorbidity adjustment in claims data analysis. However, the effects of certain implementation decisions have not been empirically examined. OBJECTIVE: To determine the effects of alternative data sources and lookback periods on the performance of Charlson scores in the prediction of mortality following hospitalization. SUBJECTS: A representative sample of 1,387 elderly patients hos…
In Search of a Good Death: Observations of Patients, Families, and Providers
Despite a recent increase in the attention given to improving end-of-life care, our understanding of what constitutes a good death is surprisingly lacking. The purpose of this study was to gather descriptions of the components of a good death from patients, families, and providers through focus group discussions and in-depth interviews. Seventy-five participants-including physicians, nurses, social workers, chaplains, hospice volunteers, patients…
Refinements of a methodology for detecting married couples in the medicare data
This article is a commentary on the methodology used by Kestenbaum in detecting married couples in the US. First the authors considered Kestenbaums efforts in conducting parallel analyses on this subject using the data sets of the Social Security Administration and his ability to confirm the main points of the argument. Likewise the authors acknowledge Kestenbaums insight that the cross-reference file can be used to link classes of husbands and w…
Impact of Individual and Market Factors on the Timing of Initiation of Hospice Terminal Care
CONTEXT: Hospice terminal care is now used by 10% to 15% of elderly Americans at variable points before their deaths. OBJECTIVE: By examining the duration of patient survival after enrollment in hospice care, we sought to identify individual and market factors associated with the timing of hospice use. DESIGN: We linked Medicare claims, census information, and Area Resource File data to form a national cohort of 151,410 hospice patients admitted …
Inventing Pain Medicine: From the Laboratory to the Clinic. Isabelle Baszanger
Construct Validity of Medicare Chemotherapy Claims: The Case of 5FU
BACKGROUND: The elderly are under represented in clinical trials of cancer therapy and the elderly who are enrolled may be unrepresentative. OBJECTIVE: To assess whether Medicare claims data might be used to understand the benefits and tolerance of chemotherapy in the general elderly population, the construct validity of Medicare 5FU claims for elderly colon cancer patients within the SEER-Medicare data set was determined. METHODS: In this valida…
Medical modelling of obesity: A transition from action to experience in a 20th century American medical textbook
Obesity is now the focus of considerable attention in the medical profession, and many have noted that obesity has been progressively medicalised. The subjection of phenomena to medical explanation, however, has been associated with both the potential to relieve and also to exacerbate the attribution of individual responsibility. In order to understand the ways in which a particular phenomenon, obesity, can be variously conceptualised at differen…
The health impact of health care on families: A Matched Cohort Study of Hospice Use by Decedents and Mortality Outcomes in Surviving, Widowed Spouses
Marriage, widowhood, and health-care use
Effect of specific aspects of community social environment on the mortality of Individuals diagnosed with serious illness
Income inequality and weight status in US metropolitan areas
Mortality after the Hospitalization of a Spouse
BACKGROUND: The illness of a spouse can affect the health of a caregiving partner. We examined the association between the hospitalization of a spouse and a partner's risk of death among elderly people. METHODS: We studied 518,240 couples who were enrolled in Medicare in 1993. We used Cox regression analysis and fixed-effects (case-time-control) methods to assess hospitalizations and deaths during nine years of follow-up. RESULTS: Overall, 383,48…
Medicine (59 works) · Psychology (53 works) · Demography (37 works) · Sociology (35 works) · Social Psychology (28 works) · Political science (24 works) · Population (24 works) · Environmental health (23 works) · Health disparities and outcomes (23 works) · Computer Science (20 works)